The effective treatments for central nervous system (CNS) diseases are impeded mostly by the existence of the blood–brain barrier (BBB). The accumulation of therapeutic drugs inside the brain is far from the therapy threshold, which is closely related to the transient circulation time of drugs and their carriers. Herein, a core–shell protein-based long-circulation delivery platform was constructed. Through in situ free radical polymerization, a zwitterionic polymer poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC) was modified on the surface to prolong the circulation lifetime with a biomimetic structure induced by a phosphorylcholine (PC) head-group similar to the lipids in the outer membrane of living cells. A cell-penetrating peptide, HIV-1 trans-activating transcriptor (TAT) was conjugated on the surface of the protein-based nanoparticles, endowing the delivery platform with BBB-crossing ability. The BBB-permeability of the nanoparticles was investigated both in vitro and in vivo. Encapsulated with zwitterionic polymer PMPC, the nanoparticles showed a long circulation lifetime due to strong resistance to nonspecific adsorption and provided a better chance for BBB penetration. The delivery platform had enhanced permeability for BBB and a longer retention time inside the brain in a healthy mouse model. Overall, the surface modification with zwitterionic polymer PMPC and cell-penetrating peptide TAT changes the circulation modality of the nanoparticles in vivo, and provides a promising pathway for BBB crossing as a potential drug delivery platform for CNS related disease therapy.
How to balance the sensitivity and signal-to-noise ratio of immunosensor remains many challenges during various diseases diagnosis. Here we develop a new microfluidic immunosensor based on surface-modified mesoporous nanofibers , and simultaneously realize an ultra-sensitivity and high signal-to-noise ratio for the detection of multiple biomarkers. In the current study, we fabricated titanium dioxide (TiO 2 )-based mesoporous electrospinning nanofibers, and modified nanofiber surface with both octadecylphosphonic acid (OPA) and poly(ethylene oxide)-poly(propylene oxide) triblock copolymer (PEO-PPO-PEO). Such nanofibers as solid substrate are covered on microfluidic channels. The porosity of our nanofibers dramatically increased the adsorption capability of antibodies, realizing an ultra sensitivity of biomarker detection. PEO-PPO-PEO modification can significantly block non-specific absorptions, obtaining a satisfied signal-to-noise ratio. For the detection of HIV p24 and interleukin 5 (IL-5), our immunosensor increased 6.41 and 6.93 fold in sensitivity and improved 504.66% and 512.80% in signal-to-noise ratio, in compared with gold standard immunoassay (ELISA) used in the clinic. Our immunosensor also broaden the linear range for the detection of HIV p24 (0.86–800 pg/ml) and IL-5 (0.70–800 pg/ml), in compared with ELISA which is 5.54–500 pg/ml for HIV p24 and 4.84–500 pg/ml for IL-5. Our work provided a guideline for the construction of advanced point-of-care immunosensor with an ultra-sensitivity and high signal-to-noise ratio for disease diagnosis.
危险品化学品经营许可证（带存储）