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A novel SiO(2)/TiO(2) composite monolithic capillary column was prepared by sol-gel technology and successfully applied to enrich phosphopeptides as a metal oxide affinity chromatography (MOAC) material. For the monolith preparation, tetramethoxysilane (TMOS) and tetrabutoxytitanium (TBOT) were used as silica and titania source, respectively, and glycerol was introduced to attenuate the activity of titanium precursor, which provided a mild synthetic condition. The prepared monolith was characterized by energy dispersive X-ray spectroscopy (EDX) and X-ray diffraction (XRD). The results revealed an approximate 1/2 molar ratio of titanium to silica as well as an atom-scale homogeneity in the framework. The scanning electron microscopy (SEM) results demonstrated an excellent anchorage between the column and the inner capillary wall, and nitrogen adsorption-desorption experiments showed a bimodal porosity with a narrow mesopore distribution around 3.6 nm. The prepared monolith was then applied for selective enrichment of phosphopeptides from the digestion mixture of phosphoproteins and bovine serum albumin (BSA) as well as human blood serum, nonfat milk, and egg white using an in-tube solid phase microextraction (SPME) system. Our results showed that SiO(2)/TiO(2) composite monolithic capillary column could efficiently enrich the phosphopeptides from complex matrixes. To the best of our knowledge, this is the first attempt for preparing the silica-metal composite monolithic capillary column, which offers the promising application of the monolith on phosphoproteomics study.

Electrical stimulation (ES) can be used to manipulate recovery after peripheral nerve injuries. Although biomaterial-based strategies have already been implemented to gain momentum for ES and engineer permissive microenvironments for neural regeneration, the development of biomaterials for specific stimuli-responsive modulation of neural cell properties remains a challenge. Herein, we homogeneously incorporate pristine carbon nanotubes into a functional self-assembling peptide to prepare a hybrid hydrogel with good injectability and conductivity. Two-dimensional (on the surface) and three-dimensional (within the hybrid hydrogel) culturing experiments demonstrate that ES promotes axon outgrowth and Schwann cell (SC) migration away from dorsal root ganglia spheres, further revealing that ES-enhanced interactions between SCs and axons result in improved myelination. Thus, our study not only advances the development of tailor-made materials but also provides useful insights into comprehensive approaches for promoting nerve growth and presents a practical strategy of repairing peripheral nerve injuries.

Biocompatible and degradable injectable materials prepared via bioorthogonal reactions are highly promising for biomedical applications because they can be formed in situ and administered in a minimally invasive way. In this work, a PEG-based injectable hydrogel was fabricated via a copper-free, strain-promoted azide-alkyne cycloaddition (SPAAC) click chemistry. Azide and cyclooctyne moieties on the PEG backbones underwent a rapid click reaction to trigger the formation of the hydrogel within several minutes. Resulting from the introduction of ester groups into the cross-linked network, the hydrogel presented pH-dependent hydrolysis and biological fast degradability. Good biocompatibility of the hydrogel was verified by in vitro cytotoxicity assay and in vivo studies. The hydrogel formed in situ after subcutaneously injecting the gel precursors into Kungming (KM) mice. The implanted hydrogel caused a mild inflammatory response in vivo, and the surrounding tissues fully recovered a week after the injection. The injectable and fast-degradable hydrogel fabricated by the bioorthogonal click reaction may be useful as biomaterials such as embolic agents for interventional therapy.

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