Ultrahigh Loading Capacity Research Articles

PTFE nanofiber cross-linked acetylene black: A flexible self-supporting semi-confined architecture for ultra-high sulfur loading and areal capacity

Lithium-sulfur batteries attract great interest due to their high energy density, sulfur abundance and environment friendly. However, the shuttle effect of lithium polysulfide and serious capacity fading especially at high sulfur loading remains a challenge for their commercial applications. In this work, we propose a scalable and feasible strategy to construct a flexible host for sulfur and catalyst carrier, in which polytetrafluoroethylene is employed as a precursor and in-situ polymerized into nanofibers to link acetylene black (PTFE NF/AB) through a blend and low temperature (∼ 180 °C) treatment process. The PTFE NF/AB exhibits semi-confined architecture for sulfur accommodation, electrolyte infiltration and electron transformation. Impressively, the electrode achieves a high areal capacity of 14.6 mAh cm−2 at the current density of 4.82 mA cm−2 with a sulfur loading of 20.6 mg cm−2. Moreover, the PTFE NF/AB architecture can be employed as the catalyst supports. The capacity can be further enhanced to 17.4 mAh cm−2 when MoS2 fabricated into the PTFE NF/AB using a ball mill approach. Assembled into a pouch cell, the PTFE NF/AB architecture delivers a high capacity of 825.4 mAh g−1 in the folded state, showing its excellent potential in the high-energy flexible territory.

Electrochemically Finely Regulated NiCo‐LDH/NiCoOOH Nanostructured Films for Supercapacitors with Record High Mass Loading, Areal Capacity, and Energy Density

AbstractThe design of supercapacitor materials with both high mass loading and high areal capacity is a major strategy to overcome relatively low energy density of supercapacitors. Herein, NiCo‐layered double hydroxide (NiCo‐LDH)/NiCoOOH composite films with both ultrahigh mass loading and high areal capacity are prepared by a two‐step cyclic voltammetry method. The films consist of NiCo‐LDH/NiCoOOH microspheres assembled with ultrafine nanosheets with highly ordered pore distribution from macropores to micropores and abundant defect active sites, which are conducive to the transport of electrolyte ions, increasing the reaction kinetics, and greatly improving the utilization of active material. The optimal film with hierarchical microstructure featuring an ultrahigh mass loading of 80 mg cm−2 not only exhibits a state‐of‐the‐art high areal capacity of 14.7 mAh cm−2, but also shows a record‐high energy density of 10.7 mWh cm−2 , as well as presents remarkable mechanical stabilityand superior capacity retention of 99% after 20000 galvanostatic charge‐discharge cycles. Moreover, by combining the experimental analysis and theoretical calculations, the mechanism of preferential conversion of the NiCo‐LDH in the subtle defect region to NiCoOOH by electrochemistry and the synergistic effect in electrochemical energy storage of the NiCo‐LDH and NiCoOOH phases is proposed.

Single-Administration Long-Acting Microarray Patch with Ultrahigh Loading Capacity and Multiple Releases of Thermally Stable Antibodies.

Current antibody (Ab) therapies require development of stable formulations and an optimal delivery system. Here, we present a new strategy to create a single-administration long-lasting Ab-delivery microarray (MA) patch, which can carry high doses of thermally stabilized Abs. The MA fabricated by an additive three-dimensional manufacturing technology can be fully embedded into the skin via a single application to deliver doses of Abs at multiple programmable time points, thus sustaining Ab concentrations in systemic circulation. We developed an MA formulation that stabilized and delivered human immunoglobulins (hIg) in a time-controlled manner while maintaining their structure and functionality. As an example, the b12 Ab─a broadly neutralizing Ab against HIV-1─maintained antiviral activity in vitro after MA manufacturing and heat exposure. Pharmacokinetic studies of MA patch-delivered hIg in rats successfully provided a proof of concept for concurrent and time-delayed Ab delivery. These MA patches codeliver different Abs, providing a tool for expanded protection against viral infections or combination HIV therapy and prevention.

Hollow Nanoporous Prussian Blue Nanocubes Enriched with Cu2+ and Loaded with Quercetin for Synergistic Tumor Therapy

Combination therapy based on Prussian blue nanoparticles (PB NPs) is particularly effective in cancer because of their outstanding photothermal properties and excellent biocompatibility. However, the application of PB in tumor therapy is hindered by their poor reactive oxygen species (ROS) production capacity, and low drug loading rate. More importantly, PB NPs could activate heat shock proteins (HSPs) in photothermal therapy, which induces the self-protection of tumor cells. Structural and functional modulation improved antitumor efficacy by enhancing reactive oxygen species (ROS) production and inhibiting heat shock protein expression. In this work, we synthesized Cu2+-enriched hollow nanoporous PB nanocubes (Cu-HNPB NCs) that enhanced the •OH generating capability of PB as Cu hybridization increases the oxidation potential of PB. Moreover, in the tumor milieu, Cu2+ release depletes glutathione (GSH) and converts to Cu+, further improving ROS levels. Excess ROS amplifies cellular oxidative stress and destroys the heat-induced formation of HSPs, thus breaking the self-protection mechanism of tumor cells. To enhance the therapeutic efficiency, quercetin (QUE) was loaded in Cu-HNPB NCs (Cu-HNPB@QUE NCs). Surprisingly, the large specific surface area (127.79 m2 g–1) endowed Cu-HNPB NCs with ultrahigh loading capacity (57.25%). As the nanoplatform enhances synergistic therapeutic effects, this study provides a new approach for designing multimodal combination nanomedicine.

Fe(III)-Naphthazarin Metal-Phenolic Networks for Glutathione-Depleting Enhanced Ferroptosis-Apoptosis Combined Cancer Therapy.

Nowadays, Fenton chemistry-based chemodynamic therapy (CDT) is an emerging approach to killing tumor cells by converting endogenous H2 O2 into cytotoxic hydroxyl radicals (·OH). However, the elimination of ·OH by intracellular overexpressed glutathione (GSH) results in unsatisfactory antitumor efficiency. In addition, the single mode of consuming GSH and undesirable drug loading efficiency cannot guarantee the efficient cancer cells killing effect. Herein, a simple one-step strategy for the construction of Fe3+ -naphthazarin metal-phenolic networks (FNP MPNs) with ultrahigh loading capacity, followed by the modification of NH2 -PEG-NH2 , is developed. The carrier-free FNP MPNs can be triggered by acid and GSH, and rapidly release naphthazarin and Fe3+ , which is further reduced to Fe2+ that exerts Fenton catalytic activity to produce abundant ·OH. Meanwhile, the Michael addition between naphthazarin and GSH can lead to GSH depletion and thus achieve tumor microenvironment (TME)-triggered enhanced CDT, followed by activating ferroptosis and apoptosis. In addition, the reduced Fe2+ as a T1 -weighted contrast agent endows the FNP MPNs with magneticresonanceimaging(MRI) functionality. Overall, this work is the debut of naphthazarin as ligands to fabricate functional MPNs for effectively depleting GSH, disrupting intracellular redox homeostasis, and enhancing CDT effects, which opens new perspectives on multifunctional MPNs for tumor synergistic therapy.

Copper carbonate nanoparticles as an effective biomineralized carrier to load macromolecular drugs for multimodal therapy

Macromolecular drugs have attracted great interest as biotherapy to cure previously untreatable diseases. For clinical translation, biomacromolecules encounter several common druggability difficulties, such as in vivo instability and poor penetration to cross physiologic barriers, thus requiring sophisticated systems for drug delivery. Inspired by the natural biomineralization via interaction between inorganic ions and biomacromolecules, herein we rationally screened biocompatible transition metals to biomineralize with carbonate for macromolecules loading. Among the metal ions, Cu2+ was found to be the best candidate, and its superiority over the widely studied Ca2+ minerals was also demonstrated. Capitalized on this finding, copper carbonate nanoparticles were prepared via a simple mixing process to co-load glucose oxidase (GOx) and a HIF-α DNAzyme (DZ), achieving ultra-high loading capacity of 61%. Upon encapsulation into nanoparticles, enzymatic activity of both drugs was passivated to avoid potential side-effects during circulation, while the drugs could be rapidly released within 1 h in response to acidic pH to fully recover their activities. The nanoparticles could accumulate into tumor via intravenous injection, facilitate the cell membrane penetration, and release the payloads of GOx, DZ and Cu2+ inside cells to exert a series of anti-tumor effects. GOx caused tumor starvation by catalytic glucose consumption, and the concomitantly generated H2O2 byproduct boosted the Cu2+-mediated chemodynamic therapy (CDT). Meanwhile, the DZ silenced HIF-α expression to sensitize both starvation therapy and CDT. As a result, a synergistic tumor growth inhibition was achieved. This work provides a simple method to prepare biomineralized nanoparticles, and offers a general approach for macromolecular drugs delivery via Cu2+-based biomineralization.

Swellable hollow periodic mesoporous organosilica capsules with ultrahigh loading capacity for hydrophobic drugs.

As a new kind of drug carrier, practical applications of hollow periodic mesoporous organosilica (HPMO) have been greatly limited by their low loading capacity for hydrophobic drugs. In this work, we demonstrated the preparation of HPMO capsules with tunable shell thickness by using 1,2-bis(triethoxysilyl)ethane as the precursor. The capsules with thin shells and thus low Young's modulus showed excellent swellability to organic solvents containing hydrophobic drugs. As a result, hydrophobic drugs, i.e., paclitaxel (PTX) could be loaded into the hollow interior of the HPMO capsules with 4nm shell at an efficiency of ca. 120%. The as-prepared PTX-loaded HPMO capsules were dispersible in aqueous media and showed improved performance in killing cancer cells compared to free PTX.

Ultrahigh-loading capacity rubber shock cell for mating of an integrated deck to jacketed legs offshore

Ultrahigh-loading capacity rubber shock cell for mating of an integrated deck to jacketed legs offshore

Environmentally Friendly Zr-Based MOF for Pesticide Delivery: Ultrahigh Loading Capacity, pH-Responsive Release, Improved Leaf Affinity, and Enhanced Antipest Activity.

The stimuli responsive pesticide delivery system (PDS) has drawn increasing attention in recent years, a system which can effectively improve the utilization of pesticides. In the current research, we report a pH responsive PDS by using carboxymethyl cellulose (CMC) modified Zr-based metal organic frameworks (UiO-66-NH2) as the nanocarrier for acetamiprid (ATP). UiO-66-NH2-CMC possesses a large surface area and abundant pores, which can effectively load ATP, and the loading rate is as high as 90.79%. Compared with free ATP, the ATP@UiO-66-NH2-CMC nanopesticide exhibits pH responsive controlled release behavior, and the pesticide can sustained release to the medium. In addition, it also shows improved leaf affinity, which makes it easier to wet the leaf surface and improve the utilization of pesticide. Therefore, ATP@UiO-66-NH2-CMC displays better antipest activity against aphids than free ATP does. Meanwhile, ATP@UiO-66-NH2-CMC shows no negative effects on the germination and growth of maize, showing good biosafety. Moreover, the ATP@UiO-66-NH2-CMC nanopesticide does not contain any toxic organic solvents or additives. Therefore, we hope that it can be a suitable candidate for plant protection and sustainable agriculture.

Nucleobase-crosslinked poly(2-oxazoline) nanoparticles as paclitaxel carriers with enhanced stability and ultra-high drug loading capacity for breast cancer therapy

Poly(2-oxazoline) (POx) has been regarded as a potential candidate for drug delivery carrier to meet the challenges of nanomedicine clinical translation, due to its excellent biocompatibility and self-assembly properties. The drug loading capacity and stability of amphiphilic POxs as drug nanocarriers, however, tend to be insufficient. Herein, we report a strategy to prepare nucleobase-crosslinked POx nanoparticles (NPs) with enhanced stability and ultra-high paclitaxel (PTX) loading capacity for breast cancer therapy. An amphiphilic amine-functionalized POx (PMBEOx-NH2) was firstly prepared through a click reaction between cysteamines and vinyl groups in poly(2-methyl-2-oxazoline)-block-poly (2‑butyl‑2-oxazoline-co-2-butenyl-2-oxazoline) (PMBEOx). Complementary nucleobase-pairs adenine (A) and uracil (U) were subsequently conjugated to PMBEOx-NH2 to give functional POxs (POxA and POxU), respectively. Due to the nucleobase interactions formed between A and U, NPs formed by POxA and POxU at a molar ratio of 1:1 displayed ultrahigh PTX loading capacity (38.2%, PTX/POxA@U), excellent stability, and reduced particle size compared to the uncross-linked PTX-loaded NPs (PTX/PMBEOx). Besides the prolonged blood circulation and enhanced tumor accumulation, the smaller PTX/POxA@U NPs also have better tumor penetration ability compared with PTX/PMBEOx, thus leading to a higher tumor suppression rate in two murine breast cancer models (E0711 and 4T1). These results proved that the therapeutic effect of chemotherapeutic drugs could be improved remarkably through a reasonable optimization of nanocarriers.

Surface Adsorption-Mediated Ultrahigh Efficient Peptide Encapsulation with a Precise Ratiometric Control for Type 1 and 2 Diabetic Therapy.

A surface adsorption strategy is developed to enable the engineering of microcomposites featured with ultrahigh loading capacity and precise ratiometric control of co-encapsulated peptides. In this strategy, peptide molecules (insulin, exenatide, and bivalirudin) are formulated into nanoparticles and their surface is decorated with carrier polymers. This polymer layer blocks the phase transfer of peptide nanoparticles from oil to water and, consequently, realizes ultrahigh peptide loading degree (up to 78.9%). After surface decoration, all three nanoparticles are expected to exhibit the properties of adsorbed polymer materials, which enables the co-encapsulation of insulin, exenatide, and bivalirudin with a precise ratiometric control. After solidification of this adsorbed polymer layer, the release of peptides is synchronously prolonged. With the help of encapsulation, insulin achieves 8 days of glycemic control in type 1 diabetic rats with one single injection. The co-delivery of insulin and exenatide (1:1) efficiently controls the glycemic level in type 2 diabetic rats for 8 days. Weekly administration of insulin and exenatide co-encapsulated microcomposite effectively reduces the weight gain and glycosylated hemoglobin level in type 2 diabetic rats. The surface adsorption strategy sets a new paradigm to improve the pharmacokinetic and pharmacological performance of peptides, especially for the combination of peptides.

Atomic controllable anchoring of uranium into zirconate pyrochlore with ultrahigh loading capacity.

Efficient immobilization of actinide wastes is challenging in the nuclear energy industry. Here, we reported that 100% substitution of Zr4+ by U6+ in a La2Zr2O7 matrix has been achieved for the first time by the molten salt (MS) method. Importantly, we observed that uranium can be precisely anchored into Zr or La sites of the La2Zr2O7 matrix, as confirmed by X-ray diffraction, Raman, and X-ray absorption spectra. This work will guide the construction of site-controlled and high-capacity actinide-immobilized pyrochlore materials and could be extended to other perovskite materials.

(Rose Bengal)/(Eosin Yellow)-Gold-Polypyrrole Hybrids: A Design for Dual Photo-Active Nano-System with Ultra-High Loading Capacity.

PurposeEnhancement of the photodynamic/photothermal efficiency of two water-soluble dyes, rose bengal (RB) and eosin yellow (EY), via conjugation to a polymeric nano-system gold-polypyrrole nanoparticle (AuPpy NPs).MethodologyA multi-step synthesis method and an in situ one-pot synthesis method were used. Loading percentage, particle size, zeta potential, morphology, UV-Vis-NIR spectrophotometry and in vitro photothermal activity were measured. Then, both hybrid nanocomposites were examined for their cytotoxicity and photocytotoxicity on HepG2 cell line as a model for cancer cells.ResultsDyes loaded in the traditional multi-step method did not exceed 9% w/w, while in the one-pot synthesis method they reached ~67% w/w and ~75% w/w for EY-AuPpy NPs and RB-AuPpy NPs, respectively. UV-Vis-NIR spectrophotometry showed that both nano-systems exhibited intense absorption in the NIR region. The mean size of the nanoparticles was ~31.5 nm (RB-AuPpy NPs) and ~33.6 nm (EY-AuPpy NPs) with zeta potential values of −26.5 mV and −33 mV, respectively. TEM imaging revealed the morphology of both hybrids, showing ultra-nano spherical-shaped gold cores in the case of RB-AuPpy NPs, and different shapes of larger gold cores in the case of EY-AuPpy NPs, both embedded in the polymer film. Conjugation to AuPpy was found to significantly reduce the dark cytotoxicity of both RB and EY, preserving the photocytotoxicity of EY and enhancing the photocytotoxicity of RB.ConclusionGold-polypyrrole nanoparticles represent an effective delivery system to improve the photodynamic and photothermal properties of RB and EY. The in situ one-pot synthesis method provided a means to greatly increase the loading capacity of AuPpy NPs. While both hybrid nanocomposites exhibited greatly diminished dark cytotoxicity, RB-AuPpy NPs showed significantly enhanced photocytotoxicity compared to the free dyes. This pattern enables the safe use of both dyes in high concentrations with sustained action, reducing dose frequency and side effects.

Fabrication, characterization and in vitro digestion of food-grade β-carotene high loaded microcapsules: A wet-milling and spray drying coupling approach

β-Carotene high loaded microcapsules were fabricated via coupling the wet-milling and spray drying without employing any organic solvent or solubilizing oil. The impact of process parameters, including milling time and spray-drying inlet temperature, on the physicochemical stability, redispersibility, micromorphology and in vitro digestion of β-carotene microcapsules was investigated. The optimized microcapsules exhibited a small average diameter after rehydration (229.4 nm) with ultrahigh encapsulation efficiency and loading capacity (99.18 % and 19.17 %, respectively). The crystalline β-carotene was not completely transformed into amorphous state with a final crystallinity of 13.79 %. The morphology of microcapsules was dependent on the milling time and spray-drying inlet temperature, and the best integrity and uniformity of microcapsules were achieved after milling for 150 min and spray-dried at 105 °C. Furthermore, the in vitro release rate of β-carotene during the simulated gastrointestinal digestion was increased from 12.08 % to 33.72 % by extending the milling time and decreasing the inlet temperature of spray drying.

Metastable interface biomimetic synthesis of a smart nanosystem for enhanced starvation/gas therapy

Glucose oxidase (GOx)-mediated starvation therapy holds great promise in cancer treatment. However, the worse hypoxia conditions result into low therapeutic efficiency, and undegradability of carriers poses potential threats to living bodies. To address this, herein a bioinspired MnO2 nanosystem with controllable surface was developed for highly efficient starvation/gas synergistic enhanced therapy. Biomimetic design and further surface modification unprecedentedly endowed the nanosystem with ultrahigh loading capacity for GOx and l-Arginine (l-Arg) and special selectivity toward cancer cells. Especially, the dissipative O2 during starvation therapy was well replenished by a positive cycle formed by the nanosystem, which continuously reproduced O2 and accelerated glucose consumption. The abundant H2O2 was further used to oxidize l-Arg into nitric oxide to realize gas therapy. In vitro and in vivo testing confirmed that this new treatment effectively blocked the nutrition and energy sources of cells to obtain excellent therapeutic effect. We reported the first experimental item of this nanosystem for inhibiting cancer cell migration. Considering the novel design concept with facile biomimetic methods, effective co-loading of endogenous substances, and good anti-tumor and anti-migration effects, this work provided new theoretical and experimental basis for starvation therapy and inspired people to design more delicate platform for cancer treatment.

A Ti2N MXene-based nanosystem with ultrahigh drug loading for dual-strategy synergistic oncotherapy.

The exploration of MXenes, especially nitride MXenes, in the field of theranostic nanomedicine is still in its infancy. Here, towards synergistic chemo-photothermal oncotherapy, we demonstrate the first kind of 2D titanium nitride (Ti2N) MXene-based nanosystem (Ti2N@oSi) for dual-strategy synergistic oncotherapy. The unique structure of Ti2N nanosheets endows the drug carriers with an ultrahigh loading capacity of 796.3% and an excellent NIR photothermal conversion efficiency of 41.6% for chemo-photothermal therapy. After being coated with a biodegradable organosilica shell, the Ti2N@oSi nanocarriers show excellent characteristics of tumor targeting, pH/glutathione/photothermal-responsive drug release and dual-drug combination chemotherapy. Both in vitro and in vivo therapeutic evaluations demonstrate the pronounced tumor growth inhibition effect and superior biocompatibility of Ti2N@oSi nanocarriers. The excellent drug loading ability, photothermal conversion ability and surface modifiability of Ti2N open up new opportunities for tumor microenvironment-targeted synergistic oncotherapy. This work is supposed to broaden the application of MXenes in nanomedicine and, particularly, provide the first sight to the biomedical application of nitride MXenes.

Metal-organic frameworks (MOFs) for biopreservation: From biomacromolecules, living organisms to biological devices

Preservation of biological entities (e.g. DNA, enzymes, viruses, microorganisms, biochips, etc.) has presented great potential in industrial catalysis and biomedical engineering due to their enhanced structural stability and biological functionality. However, technology gaps still exist for achieving high encapsulation efficiency with low performance deterioration to provide a universal preservation method for biological entities. Metal-organic frameworks (MOFs) have been demonstrated as promising platforms for encapsulation of different bioentities for their structural diversity, versatile tailorability as well as ultrahigh loading capacity. This review comprehensively summarizes the recent progress for encapsulation of bioentity within MOF ([email protected]) via post-synthetic infiltration or in situ encapsulation, and classifies into three sections: biomacromolecules, viruses and living organisms, and biological devices. MOF coating can not only behavior as protective porous exoskeletons to develop enzymatic nanoreactors that allow the access of small substrates through the narrow channel. The emergence of bio-decomposable MOFs can be also employed for preserving functional bioentities (e.g. bio-based therapeutics, clinical biomarkers, cells, viruses, diagnostic biochips, etc.) that can retain their original activities after MOF being eluted. Predictably, the MOF preservation technique might bring in the “technical innovation” in industrial and/or biomedical applications.

Metal-Organic Framework Derived Multicomponent Nanoagent as a Reactive Oxygen Species Amplifier for Enhanced Photodynamic Therapy.

Intracellular antioxidants such as glutathione (GSH) play a critical role in protecting malignant tumor cells from apoptosis induced by reactive oxygen species (ROS) and in mechanisms of multidrug and radiation resistance. Herein, we rationally design two multicomponent self-assembled photodynamic therapy (PDT) nanoagents, that is, Glup-MFi-c and Glud-MFo-c, which consist of respective GSH-passivation and GSH-depletion linkers in metal-organic frameworks encapsulated with photosensitizers for a deeply comprehensive understanding of GSH-based tumor PDT. Multicomponent coordination, π-π stacking, and electrostatic interactions among metal ions, photosensitizers, and bridging linkers under the protection of a biocompatible polymer generate homogeneous nanoparticles with satisfied size, good colloid stability, and ultrahigh loading capacity. Compared to the GSH-passivated Glup-MFi-c, the GSH-depleted Glud-MFo-c shows pH-responsive release of photosensitizer and [FeIII(CN)6] linker in tumor cells to efficiently deplete intracellular GSH, thus amplifying the cell-killing efficiency of ROS and suppressing the tumor growth in vivo. This study demonstrates that Glud-MFo-c acts as a ROS amplifier, providing a useful strategy to deeply understand the role of GSH in combating cancer.

Sensitive explosive loaded in porous cellulose for improved stability

Octogen (HMX) composites are widely concerned as defensing weapon warhead due to the superior stability and high energy density. However, there still remain huge challenges for the fabrication of HMX composites with high loading capacity as well as reduced impact sensitivity. Among the various ecofriendly materials reported to date, cellulose has been highlighted as a promising carrier for HMX because of its natural abundance, low cost, physicochemical robustness, lightweight, and recyclability. Herein, we demonstrate a straightforward, eco-friendly suspension atomization regeneration process to prepare cellulose aerogel microspheres (CAMs). Then HMX was homogeneously embedded into the porous CAMs to obtain HMX composite materials (HCMs). As a result, a three-dimensional (3D) network-structure filled with a large number of HMX particles (93.8%) was achieved with insensitive features. Specifically, the impact sensitivity was decreased by 137.13%, the friction sensitivity was reduced to 0%, and the thermal stability of composite energetic materials was also greatly improved. The detonation velocity was estimated as 8136 m/s, almost the same as the calculated value. The combination of cellulose aerogels and HMX broadens the application of cellulose in energetic materials and brings unprecedented potential for energetic aerogel materials with ultra-high loading capacity.

Fabrication of surface charge pH-sensitive multi-bumpy small magnetic bead with ultrahigh magnetic content and its ultrahigh loading capacity and salt-free rapid isolation for DNA

Gene transfection vector polyethyleneimine (PEI) was used as a cross-linking agent to crosslink the surface epoxidized magnetic nanoparticles and aggregate them to form a small magnetic bead (MB) with multiple nanoscale bumps on its surface (i.e. the multi-bumpy small magnetic bead, mbsMB). As there is a very low content of non-magnetic components (the cross-linking agent) in the magnetic bead, the mbsMB has an ultrahigh magnetic content of 81.95 % and a smaller particle size of 1.4 μm when compared with the usual medical MB. Such a small MB also has a strong magnetic force allowing it to reach the rapid separating ability of the commonly used larger medical MB which has 8 times its volume. The mbsMB has an obvious pH sensitivity of positive and negative surface charges and the salt-free isolation of DNA has been achieved based on the electrostatic interactions between mbsMB and DNA. This avoids the desalting of the isolated DNA as well as the effects of high salt concentration on its long chain helix structure. Whether in an acidic absorbing medium, an alkalinous desorbing one or a near neutral particle-storing one, the mbsMB will have obvious surface electrostatic charges. There is also its good suspension stability in an aqueous medium which provides a good condition for isolating of DNA suitable for efficiently adsorbing and desorbing. The as-prepared MB has a unique surface structure and some excellent properties, all suitable for adsorbing DNA. In addition, a large amount of commonly used gene transfection vector PEI can be cross-linked and bonded on the surface of mbsMB, whilst still having an excellent DNA-loading ability. In summary, the mbsMB has an ultrahigh capacity of 629.49 mg/g for DNA load.