Based on the self-assembly process occurring in the human body all the time, self-assembled nanomaterials were designed by the researchers. The self-assembled nanomaterials have controllability, biocompatibility and functional advantages in vivo. The self-assembled nanomaterials constructed in situ under a physiological environment display various biological characteristics which can be used for imaging, therapy, and broad clinical applications. In situ self-assembled nanomaterials can boost drug function, reduce toxic and side effects, prolong imaging time and enlarge signal-to-noise ratio. By using pathological conditions to trigger specific responses in vivo, well-ordered nanoaggregates can be spontaneously formed by multiple weak bonding interactions. The assembly shows higher accumulation and longer retention in situ. Endogenous triggers for in situ assembly, such as enzymes, pH, reactive oxygen species and ligand receptor interaction, can be used to transform the materials into a variety of controllable nanostructures including nanoparticles, nanofibers and gels through bioactivated in vivo assembly (BIVA) strategies. BIVA strategies can be applied for treatment, imaging or participate in the physiological activities of cells at the lesion site. This review summarized and prospected the design of self-assembled peptide materials based on BIVA technology and their biomedical applications. The nanostructures of the self-assembly enable some beneficial biological effects, such as assembly induced retention (AIR) effect, enhanced targeting effect, multivalent bond effect, and membrane disturbance. Thus, the BIVA nanotechnology is promising for efficient drug delivery, enhancement of targeting and treatment, as well as optimization of the biological distribution of drugs.
Drug Delivery Systems ; Humans ; Nanofibers/chemistry* ; Nanoparticles ; Nanostructures/chemistry* ; Peptides

Sepiolite--an inexpensive, resourceful, fibrous yet inoffensive mineral--made DNA transformation rapid, simple and efficient but the mechanism for DNA transformation was still unclear. Through RNA competition test, we proposed the different transforming mechanisms from the previous report. Meanwhile, we optimized the transforming method and could transfer a colony stored at 4 degrees C for a month with plasmid through sepiolite fibers. The cells could be transformed well without competent cells preparation or incubation process. In sum, this was a novel potential transforming method, which could be explored further if the chemical method and electroporation could not be used.
DNA, Bacterial ; chemistry ; genetics ; Electroporation ; methods ; Magnesium Silicates ; chemistry ; Mineral Fibers ; Nanofibers ; chemistry ; Transformation, Bacterial

Amyloid fibrils belong to a category of abnormal aggregations of natural proteins, which are closely related to many human diseases. Recently, some critical peptide sequences have been extensively studied for clarifying the molecular mechanism of natural proteins to form amyloid fibrils. In the present study, we designed a short peptide GGAAVV (GAV-6) composed of hydrophobic amino acids glycine (G), alanine (A) and valine (V) and studied its ability to form amyloid fibrils. As characterized by atomic force microscopy (AFM) and dynamic light scattering (DLS), the peptide could self-assemble into smooth nanofibers without branches. Congo red staining/binding and thioflavin-T (ThT) binding experiments show that the nanofibers formed by GAV-6 shared identical properties with typical amyloid fibrils. These results show that the designed peptide GAV-6 could self-assemble into typical amyloid fibrils, which might make it a useful model molecule to clarify the mechanism for the formation of amyloid fibrils in the future.
Amino Acid Sequence ; Amyloid ; chemistry ; Humans ; Microscopy, Atomic Force ; Models, Molecular ; Nanofibers ; chemistry ; Peptides ; chemistry

Three-dimensional poly (epsilon-caprolactone)/silk sericin (PCL/SS) porous nanofibrous scaffolds were prepared by electrospinning. The structure and properties of the scaffolds were characterized by Scanning Electron Microscope (SEM), Transmission Electron Microscope (TEM), Fourier Transform Infrared Spectroscopy (FTIR) and water contact angle instrument. Studies on cell adhension and proliferation were carried out by culturing human primary skin fibroblast cells (FEK4) on these scaffolds using SEM and MTS. The experimental results showed that the PCL/SS nanofibrous scaffolds with SS nanoparticles had porous non-woven mesh structure with nanofibrous cross-linked with each other. Fiber diameter was very uniform and precise, and the secondary structure of SS protein had not been changed. Furthermore, the capability of hydrophile increased with the SS addition, which improved FEK4 cells adhesion and proliferation on the scaffolds.
Biocompatible Materials ; chemistry ; Cell Adhesion ; drug effects ; Cells, Cultured ; Fibroblasts ; cytology ; Microscopy, Electron ; Nanofibers ; chemistry ; Polyesters ; chemistry ; Sericins ; chemistry ; Silk ; chemistry ; Spectroscopy, Fourier Transform Infrared ; Tissue Scaffolds ; chemistry

The improving effect of electrospun drug-loaded nanofibers on the solubility of poorly water-soluble drug was investigated in the present research. Drug-loaded nanofibers were successfully prepared using electrospinning process with helicid as the poorly water-soluble model drug and polyvinylpyrrolidone K60 (PVP K60) as the filament-forming matrix. Scanning electron microscopy observation demonstrated that the nanofibers had a three-dimensional continuous web structure, and had well smooth surface and a diameter between 400-600 nm. X-ray diffraction results suggested that helicid lost its original crystal structure but highly distributed into the nanofibers in an amorphous state, resulting from the hydrogen bonding interactions between the carboxylic group of PVP K60 and the hydroxyl groups of helicid. The drug-loaded nanofibers obviously improved helicid's solubility, and were able to completely release the whole drug in 60 s. Electrospun drug-loaded nanofibers can improve the solubility and release profiles of poorly water-soluble drug.
Benzaldehydes ; administration & dosage ; chemistry ; Drug Carriers ; Drug Compounding ; Electrochemical Techniques ; methods ; Microscopy, Electron, Scanning ; Nanofibers ; chemistry ; ultrastructure ; Pharmaceutical Preparations ; chemistry ; Povidone ; chemistry ; Solubility ; Spectrophotometry, Ultraviolet ; X-Ray Diffraction

Objective: To analysis the biomechanical and biocompatible properties of calcium phosphate cement (CPC) enhanced by chitosan short nanofibers(CSNF) and Arg-Gly-Asp (RGD). Methods: Chitosan nanofibers were prepared by electrospinning, and cut into short fibers by high speed dispersion. CPC with calcium phosphorus ratio of 1.5:1 was prepared by Biocement D method. The composition and structure of CPC, CSNF, RGD modified CSNF (CSNF-RGD), CSNF enhanced CPC (CPC-CSNF), RGD modified CPC-CSNF (CPC-CSNF-RGD) were observed by infrared spectrum, X-ray diffraction (XRD) and scan electron microscopy (SEM). The mechanical properties were measured by universal mechanical testing instrument. The adhesion and proliferation of MC3T3 cells were assessed using immunofluorescence staining and MTT method. Results: The distribution of CSNF in the scaffold was homogeneous, and the porous structure between the nanofibers was observed by SEM. The infrared spectrum showed the characteristic peaks at 1633 nm and 1585 nm, indicating that RGD was successfully grafted on chitosan nanofibers. The XRD pattern showed that the bone cement had a certain curability. The stain-stress test showed that break strengths were (17.74±0.54) MPa for CPC-CSNF and (16.67±0.56) MPa for CPCP-CSNF-RGD, both were higher than that of CPC(all P<0.05). The immunofluorescence staining and MTT results indicated that MC3T3 cells grew better on CPC-CSNF-RGD after 240 min of culture(all P<0.05). Conclusion: CSNF-RGD can improve the biomechanical property and biocompatibility of CPC, indicating its potential application in bone tissue repair.
3T3 Cells ; Animals ; Biocompatible Materials ; Bone Cements ; chemistry ; metabolism ; pharmacology ; Calcium Phosphates ; metabolism ; Cell Proliferation ; drug effects ; Chitosan ; chemistry ; pharmacology ; Mice ; Nanofibers ; chemistry ; Oligopeptides ; chemistry

Different spider fibroin non crystalline motifs GGAS and GPGGY were inserted into the middle of RADA16-I . The resulting peptides were R1 (n-RADARADAGGASRADARADA-c) and R2 (n-RADARADAGPGGYRADARADA-c). Fourier transform infrared spectrum (FTIR) was used to identify the secondary structure, while atomic force microscopy (AFM) and transmitting electron microscope (TEM) were used to investigate nanofiber formation of the peptides. These results illustrate that R1 and R2 form random coils and self-assemble into short fibrillar nanostructures. R1 and R2 display a noticeable change in the formation of nanofibers with time. They become longer and wider with the increase of beta-sheet content. R1 forms less and longer fibers than R2; the nanofibers formed by R2 have bend. These characteristics provide a close correlation for the roles of amino acid sequence and beta-sheet structure in nanofiber formation.
Amino Acid Sequence ; Amino Acid Substitution ; Animals ; Fibroins ; chemistry ; genetics ; Microscopy, Atomic Force ; Nanofibers ; chemistry ; Peptides ; chemistry ; Spectroscopy, Fourier Transform Infrared ; Time Factors

Since the release rate of protein in hydrogels is directly dependent upon the size of the protein and the hydrogel, how to deliver low molecular weight protein for prolonged periods has always been a problem. In this article, we present a usage of self-assembling peptide (P3) with the RGD epitope on its N terminus. The concentration of the released insulin-like growth factor 1 (IGF-1) was determined by UV-vis spectroscopy and the release kinetics suggested a notable reduction of the IGF-1 release rate. Cell entrapment experiments revealed that IGF-1 delivery by biotinylated nanofibers could promote the proliferation of the mouse chondrogenic ATDC5 cells when compared with cells embedded within nanofibers with untethered IGF-1.
Animals ; Biotin ; Cell Line ; Delayed-Action Preparations ; Drug Carriers ; chemistry ; Hydrogels ; chemistry ; Insulin-Like Growth Factor I ; pharmacology ; Mice ; Nanofibers ; Oligopeptides ; chemistry

OBJECTIVE: To investigate and compare the growth of human fetal retinal pigment epithelial (RPE) cells seeded onto electrospun polyamide nanofibers (EPN) or etched pore polyester (EPP), and, further, to explore their possible use as prosthetic Bruch's membrane. METHODS: Human fetal RPE cells were planted onto the EPN, EPP and plastic (control) substrates in Transwells. The cultures were assessed with respect to cell attachment at 2, 4, 8 hours and proliferation at 1, 4, 8 days after seeding. Growth and morphology of the cells were monitored under the phase contrast microscope, and the phenotype was identified by immunofluorescence staining with antibodies against tight junction protein ZO-1. Strips of single EPP coated with nothing or EPP coated with EPN was differently implanted into the subretinal space of two P21 RCS rats for two weeks and the histologic slides of the retina were assessed. RESULTS: Cultured human fetal RPE cells were attached to either EPN or EPP substrates (with seeding on plastic substrate as control). After 8 h, the numbers of adherent cells in the EPN, EPP and control groups were 1.23*10(5)/cm(2), 1.70*10(5)/cm(2), and 1.64*10(5)/cm(2), respectively. The number of RPE cells attached to EPN was obviously less than that to both EPP and control (P<0.05). On the first day, the proliferation of cells on EPN was less than that of EPP and control (P<0.05); but by the 8th day in culture, the proliferation of cells on EPN had increased and was higher than proliferation on both EPP and control (P<0.05). All of the RPE cells cultured on EPN and EPP substrates were in monolayer, and the EPN-attached cells resembled the inner collagenous layer of Bruch's membrane. Immunofluorescence staining showed that the RPE cells cultured on EPN and EPP substrates adopted a higher expression of ZO-1 than that on the plastic control substrate. Subretinal implantation of either EPP alone or EPP as a carrier for free EPN for 2 weeks in P21RCS rats resulted in an expected encapsulation and loss of photoreceptor layer. No toxicity or other adverse reaction was observed in the vicinity of the transplant. CONCLUSION EPN and EPP could maintain human fetal RPE cell attachment and proliferation. Both EPN and EPP appeared to be grossly tolerance and biocompatible with subretinal implantation. EPN represents an intriguing prospect for prosthetic Bruch's membrane replacement because of its similarity in structure to native Bruch's membrane.
Animals ; Biocompatible Materials ; chemistry ; Bruch Membrane ; Cell Proliferation ; Cells, Cultured ; Fetus ; Humans ; Membranes, Artificial ; Nanofibers ; chemistry ; Polyesters ; chemistry ; Porosity ; Rats ; Retinal Pigment Epithelium ; cytology ; growth & development ; Tissue Engineering

The present research was aimed to explore the biocompatibility of IKVAV self-assembling peptide nanofiber scaffold with olfactory ensheathing cells (OECs) of rats. The OECs were seeded onto the surface of coverslips covered with IKVAV self-assembling peptide nanofiber scaffold hydrogel (2D culture system), and implanted within IKVAV self-assembling peptide nanofiber scaffold hydrogel (3D culture system), respectively. The adhesion, viability of OECs were observed with inverted microscope. Then the characteristics for survival and adhesion of cells by image processing were observed, and statistical analysis on the number of S-100 positive cell, the area of the cell bodies and the perimeter of the cell and MTT method were carried out. It was found that the OECs could survive and migrate in IKVAV self-assembling peptide nanofiber scaffold. The result of the cell MTT exam, of the shape and quantity of cells had no significant difference compared to those of the OECs cultured with poly-L-lysine (PLL). It has been proved that IKVAV self-assembling peptide nanofiber scaffold has good biocompatibility with rat OECs.
Animals ; Animals, Newborn ; Biocompatible Materials ; chemistry ; Cell Proliferation ; Cells, Cultured ; Hydrogel, Polyethylene Glycol Dimethacrylate ; chemistry ; Laminin ; chemistry ; Nanofibers ; chemistry ; Olfactory Bulb ; cytology ; drug effects ; Peptide Fragments ; chemistry ; Rats ; Rats, Sprague-Dawley ; Tissue Engineering ; methods ; Tissue Scaffolds ; chemistry