Metallic Lanthanum (III) Hybrid Magnetic Nanocellulose Composites for Enhanced DNA Capture via Rare-Earth Coordination Chemistry

Abstract

Lanthanide rare earth elements possess significant promise for material applications owing to their distinctive optical and magnetic characteristics, as well as their versatile coordination capabilities. This study introduced a lanthanide-functionalized magnetic nanocellulose composite (NNC@Fe₃O₄@La(OH)₃) for effective phosphorus/nitrogen (P/N) ligand separation. The hybrid material employs the adaptable coordination geometry and strong affinity for oxygen of La³⁺ ions to show enhanced DNA-binding capacity via multi-site coordination with phosphate backbones and bases. This study utilized cellulose as a carrier, which was modified through carboxylation and amination processes employing deep eutectic solvents (DES) and polyethyleneimine. Magnetic nanoparticles and La(OH)₃ were subsequently incorporated into the cellulose via in situ growth. NNC@Fe₃O₄@La(OH)₃ showed a specific surface area of 36.2 m²·g⁻¹ and a magnetic saturation intensity of 37 emu/g, facilitating the formation of ligands with accessible La³⁺ active sites, hence creating mesoporous interfaces that allow for fast separation. NNC@Fe₃O₄@La(OH)₃ showed a significant affinity for DNA, with adsorption capacities reaching 243 mg/g, mostly due to the multistage coordination binding of La³⁺ to the phosphate groups and bases of DNA. Simultaneously, kinetic experiments indicated that the binding process adhered to a pseudo-secondary kinetic model, predominantly dependent on chemisorption. This study developed a unique rare-earth coordination-driven functional hybrid material, which is highly significant for constructing selective separation platforms for P/N-containing ligands.

1. Introduction

Lanthanide elements (Ln) consist of 15 metals ranging from lanthanum (La) to lutetium (Lu), all of which have highly similar chemical properties [1,2]. Because of their unusual internal 4f electron structures, which give them unique optical, catalytic, and magnetic capabilities, lanthanide elements hold a prominent place in inorganic chemistry [2]. Furthermore, because of their distinct electron localization, varied oxidation states, and adaptable coordination skills, lanthanide ions can combine with a variety of ligands to generate complexes that have potential uses in chemical catalysis, biosensing, energy development, and high-resolution imaging.

Lanthanide ions (Ln³⁺) exhibit an excellent coordination capacity with oxygen and nitrogen atoms; hence, molecules with O and N donor atoms are frequently selected as ligands for the synthesis of lanthanide complexes [3,4]. For instance, ligands with imine, amide, carboxylate, or phosphate groups can readily bind with Ln³⁺. Lanthanide elements have a higher affinity for polydentate ligands because of their high coordination number (8–12 in solution) [5]. Recent studies have demonstrated exceptional binding affinities between Ln and biomolecules [6], such as peptides, proteins, and nucleic acids. Ln³⁺ can form stable complexes with peptides and stabilize proteins, potentially substituting for Ca²⁺ in biological systems [7]. Furthermore, Ln may both sense or identify nucleic acid molecules and attach to the phosphate ester bonds of nucleic acids, demonstrating considerable hydrolytic activity. Therefore, the integration of lanthanide metals with biomolecules to create innovative functional materials utilizing rare earth elements has emerged as a focal point in inorganic and materials chemistry research.

With the rapid development of nanotechnology, inorganic nanoparticles and nanocomposites have found widespread application in various fields of modern industry due to their regular shapes, hard textures, biodegradability, and surface functionalization. The design and synthesis of lanthanide metal coordination nanoparticles are essential for the utilization of lanthanide elements. Lanthanide metal nanoparticles generally manifest as oxides or hydroxides [8]. Nonetheless, their elevated surface energy renders them susceptible to agglomeration, leading to hindering stability and controllability, which considerably obstructs their practical applicability [8,9]. It is simple to produce a stable structure by fixing metal nanoparticles onto a substrate through in situ growth. A great carrier platform for creating organic-inorganic hybrid materials is cellulose, a naturally occurring, renewable, hydroxyl-rich biopolymer. Nano-cellulose, in particular, has a high specific surface area, multi-level pore structure, and is simple to functionalize [10]. Cellulose has been shown to improve the stability and effectiveness of metal nanoparticles [11]. Nowadays, a lot of research has been performed on hybrid cellulose composites such as TiO₂, CuO, ZnO, and Fe₃O₄ [12]. Furthermore, the integration of inorganic or organic materials with magnetic nanoparticles can enhance the recyclability and manipulability of compliant materials, offering novel insights for the advancement of sustainable functional materials.

Deoxyribonucleic acid (DNA) is not only a crucial hereditary material but also functions as a notable ligand for various metal ions [13,14]. Its interaction with Ln³⁺ transpires via both the phosphate backbone and the bases. The phosphate groups in DNA can interact with Ln³⁺ by electrostatic forces, whereas the nitrogenous ligands from the bases can create complexes with Ln³⁺ nucleotides, especially with adenosine or guanosine phosphates [15,16,17]. Considering the robust affinity of Ln³⁺ for DNA, exploiting the coordination benefits of rare earth elements to construct inorganic–organic hybrid nanomaterials can enhance comprehension of the coordination dynamics between rare earth metals and biomolecules.

This research employed a sustainable and efficient approach to create a controlled inorganic–organic hybrid nanocomposite material consisting of lanthanum-doped magnetic nano-cellulose. The production, structure, and specific interaction with DNA were thoroughly examined. The binding mechanism between lanthanum-doped magnetic nano-cellulose and biomolecules was clarified through adsorption analysis and structural confirmation, providing mechanistic insights for the development of innovative inorganic–organic composite materials.

2. Results and Discussion

2.1. Structure and Characteristics of Lanthanum Hybrid Magnetic Nanocellulose

A schematic diagram of the rare earth metal-hybrid magnetic nano-cellulose composite material (NNC@Fe₃O₄@La(OH)₃) preparation procedure is presented in Figure 1. To create carboxylated cellulose, microcrystalline cellulose (MCC) is first treated with a deep eutectic solvent to shrink it and change some of its hydroxyl groups into carboxyl groups (CNC). After that, polyethyleneimine is used to create amino-modified cellulose (NNC). Lastly, rare earth metal hybrid magnetic nano-cellulose composite materials are created by using metal salts to create a metal-hybrid structure on the cellulose surface in situ in an alkaline environment.

Figure 2a,b display the micrographs of microcrystalline cellulose and nano-cellulose. Figure 2a illustrates the original microcrystalline cellulose, characterized by greater dimensions and an irregular shape, with a diameter of roughly 50 μm. Figure 2b illustrates nanocellulose derived from treatment with deep eutectic solvent (DES). The image illustrates a notable decrease in cellulose size, suggesting that the cellulose may have undergone partial dissolution and subsequent reprecipitation, resulting in the formation of finer fibers. Figure 2c presents the infrared spectrum, revealing alterations in the cellulose structure. MCC displays the conventional cellulose structure, whereas CNC reveals a distinctive peak of carboxyl groups at 1730 cm⁻¹. In NNC, the distinctive peak of carboxyl groups vanishes, but a characteristic peak for -NH₂ at 1600 cm⁻¹ emerges, indicating additional chemical alteration and the successful incorporation of amino groups [18].

Figure 3a displays the infrared spectrum of metal-hybridized NNC, highlighting alterations in chemical structure throughout the preparation process. NNC@Fe₃O₄ displays a pronounced Fe-O vibration at 580 cm⁻¹ in contrast to NNC. The introduction of La(OH)₃ results in a peak at 1383 cm⁻¹ (La-O) and broadens the O-H stretching band at 3609 cm⁻¹, indicating the presence of hydroxyl groups in La(OH)₃. Infrared data further validate the association of La with NNC@Fe₃O₄. Figure 3b illustrates the chemical composition and characteristic peaks of binding energy corresponding to the electronic energy levels of MCC, NNC, NNC@Fe₃O₄, and NNC@Fe₃O₄@La(OH)₃. All samples display distinct C1s signals from C-C, C-O, and C=O bonds in cellulose, along with notable O1s signals from hydroxyl or carboxyl groups in cellulose molecules [18]. The N1s peak (400 eV) is attributed to nitrogen derived from amino functional groups in NNC. The Fe 2p peak at 710 eV is indicative of iron derived from the magnetic nanoparticles Fe₃O₄. The detection of Fe 2p signals in NNC@Fe₃O₄ and NNC@Fe₃O₄@La(OH)₃ signifies the effective integration of Fe₃O₄; La 3d (834.7 eV) pertains to lanthanum, derived from La(OH)₃ nanoparticles, confirming the successful inclusion of La [19]. Figure 3c illustrates the X-ray diffraction pattern of NNC@Fe₃O₄@La(OH)₃. Cellulose displays a specific diffraction peak at 2θ = 22.6°, indicative of its crystalline structure [20]. NNC@Fe₃O₄@La(OH)₃ exhibits distinct peaks at 30.1° (220), 35.5° (311), 43.1° (400), 53.7° (422), 57.0° (511), and 62.6° (440), predominantly ascribed to Fe₃O₄ (PDF#19-0629), thereby validating the spinel crystal structure. NNC@Fe₃O₄@La(OH)₃ displays specific crystalline peaks at 15.3° (100), 27.8° (101), 39° (201), 47.9° (211), and 54.5° (112), aligning with the crystalline peaks of La(OH)₃ (PDF#36-1481). The crystal structure, characteristic of rare earth hydroxides, is part of the hexagonal crystal system and exhibits a rod-like configuration (Figure 3d), signifying that lanthanum has effectively integrated with cellulose as La(OH)₃ [21].

The specific surface area of nanoparticles plays a crucial role in determining the adsorption performance of materials. Figure 4 illustrates the BET isotherm spectra for MCC, NNC, and NNC@Fe₃O₄@La(OH)₃. The specific surface area of MCC measures 1.1 m²·g⁻¹. In contrast, NNC has a specific surface area of 12.2 m²·g⁻¹, largely due to the smaller size of NNC particles, which are usually stored in liquid form. Upon drying, these particles tend to agglomerate, resulting in an increase in size without a corresponding rise in specific surface area. When compared to NNC, the specific surface area of NNC@Fe₃O₄@La(OH)₃ rises to 36.2 m²·g⁻¹, primarily attributed to the deposition of Fe₃O₄ and La(OH)₃, which enhances the roughness of the cellulose structure. In addition, the pore diameter (d_p) of MCC, NNC, and NNC@Fe₃O₄@La(OH)₃ are mesoporous structures, and the pore volume (V_p) of NNC@Fe₃O₄@La(OH)₃ is significantly increased compared to cellulose without rare earth metals. Therefore, NNC@Fe₃O₄@La(OH)₃ has a high specific surface area and high pore volume, which is favorable for DNA adsorption.

The thermal stability of materials is intricately linked to their structural composition. Figure 5a illustrates the variation in mass with temperature during the heating process for MCC, CNC, NNC, NNC@Fe₃O₄, and NNC@Fe₃O₄@La(OH)₃. MCC exhibits excellent thermal stability up to 320 °C; however, it undergoes rapid decomposition at approximately 350 °C, resulting in a char yield of less than 10%. The thermal stability of CNC and NNC is lower than that of MCC, mainly because of the reduced cellulose particle size and the presence of carboxyl and amino side chains, which increase their vulnerability to thermal decomposition. Nonetheless, NNC shows an increased char residue rate (30%), mainly due to the incorporation of amino groups, which could modify the thermal decomposition pathway of cellulose [18]. Furthermore, amino groups produce non-reactive flame-retardant gases when subjected to thermal decomposition, thereby improving the char formation potential of NNC. The composite NNC@Fe₃O₄@La(OH)₃ demonstrates enhanced thermal stability and an increased char yield (47%) in comparison to NNC, mainly attributed to the physical barrier created by the metal oxide coating on the cellulose surface. NNC@Fe₃O₄@La(OH)₃ exhibits superior thermal stability compared to NNC@Fe₃O₄, suggesting that the incorporation of La(OH)₃ results in a denser and more stable structure.

Magnetic nanoparticles provide swift recovery, the ability to be reused, and adaptable handling capabilities. This investigation incorporates Fe₃O₄ into the composite material to improve its manipulability. Figure 5b illustrates the hysteresis loops of NNC@Fe₃O₄ and NNC@Fe₃O₄@La(OH)₃, with both demonstrating characteristic S-shaped hysteresis loops. While the magnetic induction of NNC@Fe₃O₄@La(OH)₃ is marginally lower than that of NNC@Fe₃O₄, both demonstrate zero coercivity and remanence, signifying that they both exhibit superparamagnetic behavior.

2.2. Adsorption Behavior and Kinetics

To explore the interaction behavior between lanthanum hybrid magnetic nano-cellulose nanocomposites and DNA, adsorption isotherm tests for DNA adsorption were performed on NNC@Fe₃O₄ and NNC@Fe₃O₄@La(OH)₃ at 25 °C (Figure 6a). The DNA adsorption capacity of NNC@Fe₃O₄ was found to be 67 mg/g, primarily due to the electrostatic attraction between the positively charged amino groups of NNC and the negatively charged DNA. In contrast, for NNC@Fe₃O₄@La(OH)₃, the maximum adsorption capacity increased to 211 mg/g, suggesting that the incorporation of rare earth elements significantly improves DNA adsorption performance. The enhancement in adsorption capacity of the NNC@Fe₃O₄@La(OH)₃ composite is ascribed to the active La(OH)₃, which improves the specific surface area and offers more active adsorption sites [22]. In addition, compared with DNA adsorption materials reported in the literature (Table S1), NNC@Fe₃O₄@La(OH)₃ has a higher DNA adsorption capacity.

To enhance the understanding of the adsorption mechanism of NNC@Fe₃O₄@La(OH)₃, two established isotherm models—Langmuir (Equation (S3)) and Freundlich (Equation (S4))—were employed to analyze the adsorption isotherm data [23]. The parameters q_m and k_L were calculated from the intercept and slope of the linear plot of C_e/q_e against Ce (Figure 6b). The Langmuir isotherm indicates that the maximum adsorption capacity of NNC@Fe₃O₄@La(OH)₃ for DNA is 243 mg/g. Furthermore, the n value derived from the Freundlich model was 1.67 (Figure 6c), which lies within the favorable range of 1 to 10, suggesting that the adsorption process is indeed beneficial [22,24]. The results and analysis suggest that both the Langmuir and the Freundlich isotherm models demonstrate the NNC@Fe₃O₄@La(OH)₃ composite’s strong adsorption affinity for DNA (Figure 6d). The data presented in Figure 6b,c reveal that the correlation coefficient for the Langmuir model (0.965) surpasses that of the Freundlich model. This result indicates a dominance of surface adsorption sites, implying that chemical adsorption plays a significant role. Lanthanum engages in multi-coordinate interactions with the phosphate backbone or bases of DNA, leading to adsorption behavior that aligns with single-layer adsorption. The saturation capacity of monolayer adsorption is influenced by the availability of surface sites for coverage [24]. NNC@Fe₃O₄@La(OH)₃ provides an increased number of active sites and a greater specific surface area.

In order to clarify the adsorption mechanism of DNA on the NNC@Fe₃O₄@La(OH)₃ composite material, both pseudo-first-order (Equation (S5)) and pseudo-second-order kinetic (Equation (S6)) models were utilized to analyze the experimental data [22,23]. Figure 6e,f illustrate the kinetics of the adsorption process and fitting plots for the pseudo-second-order model, respectively. The pertinent parameters identified from the previously discussed kinetic models are illustrated in Figure 6f and Figure S1. The R² values of the two fitting equations indicate that the correlation coefficient for the first-order kinetic fitting is relatively low, and there is a significant difference between the equilibrium adsorption capacity obtained from the fitting and the experimental equilibrium adsorption capacity. The second-order kinetic fitting values align well with the experimental data, showing a high correlation coefficient for DNA adsorption on NNC@Fe₃O₄@La(OH)₃ (R² > 0.999). Consequently, the second-order model most accurately characterizes the adsorption behavior of NNC@Fe₃O₄@La(OH)₃. Furthermore, the theoretical values of q_e derived from the second-order model show greater alignment with the experimental values obtained. The findings suggest that the adsorption behavior of NNC@Fe₃O₄@La(OH)₃ adheres to the second-order kinetic model. The results and analysis indicate that the adsorption of DNA by NNC@Fe₃O₄@La(OH)₃ is mainly influenced by chemisorption via coordination.

2.3. Mechanism Analysis

To elucidate the coordination behavior of NNC@Fe₃O₄@La(OH)₃ with respect to DNA, XPS was utilized to examine the interaction between NNC@Fe₃O₄@La(OH)₃ and DNA. DNA primarily consists of a phosphate backbone, sugar molecules, and nitrogenous bases. Figure 7a presents the XPS P2p curves of NNC@Fe₃O₄@La(OH)₃ prior to and following DNA adsorption. Figure 7a illustrates that following DNA adsorption, a new element P emerged at a binding energy of 133.2 eV, suggesting a strong attachment of DNA to NNC@Fe₃O₄@La(OH)₃. Furthermore, as illustrated in Figure 7b, the binding energy of La3d displays a red shift following adsorption, suggesting that NNC@Fe₃O₄@La(OH)₃ has experienced significant coordination interactions with the phosphate backbone nucleobases. This interaction modifies the chemical environment of La3d, resulting in alterations to its binding energy [25]. Figure 7c,d illustrate the XPS N1s spectra prior to and following adsorption. Figure 7c clearly indicates that prior to adsorption, the N1s binding energy is predominantly associated with the amino groups on NNC. Following adsorption, the chemical environment of N1s experiences notable alterations, encompassing not just the nitrogen from the bases in DNA but also the emergence of protonated amino groups and La-N bonds (Figure 7d) [25]. This suggests that NNC@Fe₃O₄@La(OH)₃ could demonstrate electrostatic attraction and metal coordination interactions with DNA [4,5]. Furthermore, Figure 7e,f illustrate the XPS O1s spectra prior to and following adsorption. In the pre-adsorption phase, the O1s binding energy predominantly relates to the C-O bonds in cellulose, the Fe-O bonds in Fe₃O₄, and the La-O bonds in La(OH)₃. Following DNA adsorption, the binding energy at 535.5 eV reveals the C-O-N structure of DNA, highlighting the interaction between NNC@Fe₃O₄@La(OH)₃ and DNA.

3. Materials and Methods

3.1. Chemicals and Reagents

Microcrystalline cellulose of premium purity (diameter 20–50 μm) was purchased from Sinopharm Chemical Reagents Co., Ltd. (Shanghai, China) Sodium chloride, polyethyleneimine (Mw 10,000), ammonium iron (II) sulfate hexahydrate, ammonium iron (III) sulfate dodecahydrate, aqueous ammonia solution (25−28 wt%), sodium hydroxide, lanthanum nitrate hexahydrate, sodium chloride, polyethylene glycol (PEG 6000), anhydrous ethanol, choline chloride, oxalic acid dihydrate, nickel oxide, hydrochloric acid, and dimethyl sulfoxide are all analytical grade, purchased from Shanghai Macklin Biochemical Technology Co., Ltd. (Shanghai, China) Deoxyribonucleic acid (salmon extract, purity > 90%) was purchased from Shanghai Yuanye Biotechnology Co., Ltd. (Shanghai, China).

3.2. Preparation of Carboxylated Nano-Cellulose (CNC)

First, 3 g of microcrystalline cellulose was incorporated with 30 g of a deep eutectic solvent (DES, with a molar ratio of choline chloride to oxalic acid dihydrate of 1:2) and mixed at 80 °C until a clear and transparent solution was achieved. Subsequently, the mixture was agitated at 400 rpm in a water bath maintained at 95−100 °C for a duration of 2 h. The reaction mixture was ultimately frozen at −20 °C for 24 h and subsequently thawed at ambient temperature. The material was subjected to two washes with anhydrous ethanol and three washes with ultra-pure water until colorless, resulting in carboxylated nano-cellulose (CNC).

3.3. Preparation of Amino-Modified Nanocellulose (NNC)

The 2 g of CNC were dispersed in 100 mL of water. Then, 4 g of polyethyleneimine was added, and the mixture was mixed completely. The pH was adjusted to 1.5, and the mixture was stirred at ambient temperature for 1.5 h. The material was washed three times, freeze-dried for 48 h, and amino-modified cellulose (NNC) was yielded.

3.4. Synthesis of NNC@Fe₃O₄

First, 6.8 g of ammonium iron (II) sulfate hexahydrate and 10.4 g of ammonium iron (III) sulfate dodecahydrate were dissolved in 500 mL of deionized water. The 4.0 g of NNC were added, and the mixture was exposed to ultrasonic stirring for 30 min. Subsequently, the pH was modified to 10 utilizing a 6 mol/L ammonia solution. After stabilization of the pH, the mixture was mechanically stirred at 50 °C in a water bath for 1 h. Following the reaction, the mixture was allowed to cool to ambient temperature. Following segregation of the solution layers, an external magnetic field was applied to facilitate their separation. The material was rinsed several times with water until neutral, then freeze-dried under vacuum until constant weight was achieved to obtain magnetic nano-cellulose (NNC@Fe₃O₄).

3.5. Synthesis of NNC@Fe₃O₄@La(OH)₃

First, 1.5 g of magnetic nano-cellulose (NNC@Fe₃O₄) was dispersed in 100 mL of 10% ethanol, and 5 mmol of lanthanum nitrate hexahydrate was incorporated. The mixture was sonicated for 15 min, stirred at ambient temperature for 2 h, heated to 60 °C, and then 10 mL of a 2 M sodium hydroxide solution was gradually introduced. The reaction was continued for 2 h after the addition. Heating was subsequently discontinued, and the mixture was stirred at room temperature for 24 h. Magnetic separation, washing, and vacuum drying were then performed, resulting in La(OH)₃-hybridized magnetic nanofibers (NNC@Fe₃O₄@La(OH)₃).

3.6. Characterization

Scanning electron microscopy (SEM, SU1510 model, Hitachi, Tokyo, Japan) and transmission electron microscopy (TEM, JEM-2100 model, JEOL, Tokyo, Japan) were used to examine sample structures. A Fourier transform infrared spectrometer (FTIR, Vertex 70 model, Molecular Devices, San Jose, CA, USA) was used for infrared examination, having a scanning range of 4000–400 cm⁻¹. The material surface’s elemental composition and chemical state were examined using X-ray photoelectron spectroscopy (XPS, Thermo Fisher Scientific, Waltham, MA, USA). X-ray diffraction (XRD) analysis was performed by XRD-7000 (Suzhou Sailiwei, Suzhou, China). For testing, samples were placed in XRD plates with a 10–80° scanning range and 5°/min scanning speed. A thermal gravimetric analyzer (TG209F3 model, Netzsch, Selb, Germany) was used to evaluate the material’s thermal stability. The sample mass was 10 mg, and the testing temperature was 50–800 K in nitrogen. We used a specialized surface area tester (ASAP2460 model, Micromeritics, Norcross, GA, USA) to analyze surface area. The saturation magnetization of samples was measured at 300 K using a vibrating sample magnetometer (VSM, 4HF model, ADE, Chicago, IL, USA) with a magnetic field strength of ±10,000 Oe. The resulting magnetization curves were plotted to evaluate the material’s characteristics.

3.7. Preparation of DNA Solution

Salmon sperm DNA was used as the model compound to assess the separation effectiveness of NNC@Fe₃O₄@La(OH)₃ toward DNA in order to examine the DNA capture capability of metal-hybrid magnetic chitosan. To create DNA standard solutions with varying quantities, salmon sperm DNA was first dissolved in sterile deionized water.

3.8. Adsorption Behavior of NNC@Fe₃O₄@La(OH)₃

In a 1.5 mL EP tube, 900 μL of binding buffer (10 wt% PEG, 2 M NaCl, pH = 4.0), 100 μL of an aliquot of the pre-determined concentration DNA solution, and 1 mg NNC@Fe₃O₄@La(OH)₃ were combined. After that, the mixture was shaken sporadically for 10 min at room temperature. An external magnet is then used to accomplish magnetic separation. A Nanodrop 2000 UV detector (Thermo Fisher Scientific, Waltham, MA, USA) is used to determine the DNA concentration at 260 nm after the supernatant has been thoroughly removed. The difference between the concentration of DNA before and after separation is used to compute the yield of DNA extraction. The adsorption capacity of DNA was determined by the following Equation (S1) (Refer to Supplementary Materials).

3.9. Kinetics of Adsorption

The 5 mg of NNC@Fe₃O₄@La(OH)₃, 500 μL of a 30 mg/mL DNA standard solution, and 4.5 mL of binding buffer (10 wt% PEG, 2 M NaCl, pH = 4.0) were put into a 5 mL centrifuge tube. And the mixture was shaken. Samples were collected at the specified adsorption periods. The volume of each sample was roughly 10 μL. Equation (S2) was used to determine the DNA adsorption capacity q_t at various adsorption times.

4. Conclusions

This study achieved the successful synthesis of a novel lanthanum (III)-functionalized magnetic nano-cellulose hybrid material (NNC@Fe₃O₄@La(OH)₃). The systematic characterization demonstrated that La³⁺ effectively hybridized with magnetic nano-cellulose, showing a high specific surface area and superparamagnetism. The findings from the adsorption studies indicate that the material demonstrates a remarkable affinity for DNA, achieving a maximum adsorption capacity of 243 mg/g. The fundamental mechanism is related to the chemical adsorption arising from the strong P/N coordination of La³⁺. This study highlights the considerable promise of rare earth ions (La³⁺) in the creation and advancement of innovative inorganic hybrid materials with targeted element recognition and capture capabilities. It offers new materials and theoretical insights that could broaden the use of rare earth-based materials in fields such as separation science and the synthesis of inorganic–organic functional molecular materials.