Xiying Fan,Xinying Peng,Tingting Wang,Yi Gu,Guochuan Sun,Qinghui Shou,Haipeng Song,Rui Nian,Wenshuai Liu
This work aimed to establish a simple and feasible method to obtain silk fibroin nanoparticles (SFNPs) with uniform particles size, and then modify the SFNPs with nanobody (Nb) 11C12 targeting the proximal membrane end of carcinoembryonic antigen on the surface of colorectal cancer (CRC) cells. The regenerated silk fibroin (SF) was isolated using ultrafiltration tubes with a 50 kDa molecular weight cut-off, and the retention fraction (named as SF > 50 kDa) was further self-assembled into SFNPs by ethanol induction. Scanning electron microscope (SEM) and high-resolution transmission electron microscop showed that the SFNPs with uniform particles size were formed. Due to electrostatic adsorption and pH responsiveness, SFNPs have been proved to effectively load and release the anticancer drug doxorubicin hydrochloride (DOX) (DOX@SFNPs). Further, targeting molecule Nb 11C12 was used to modify these nanoparticles, constituting the targeted outer layer of the drug delivery system (DOX@SFNPs-11C12), achieving precise localization to cancer cells. The release amount of DOX observed from in vitro drug release profiles increased as follows: pH 7.4 < pH 6.8 < pH 5.4, demonstrating that the DOX release could be accelerated in a weakly acidic environment. In vitro cytotoxicity experiments displayed that SFNPs-11C12 nanoparticles exhibited good safety and biocompatibility. Drug-loaded nanoparticles, DOX@SFNPs-11C12, led to higher LoVo cells apoptosis compared to DOX@SFNPs. Fluorescence spectrophotometer characterization and confocal laser scanning microscopy further showed that the internalization of DOX was highest in the DOX@SFNPs-11C12, certifying that the introduced targeting molecule enhanced the uptake of drug delivery system by LoVo cells. This study provides a simple and operational approach to developing an optimized SFNPs drug delivery system modified by targeting Nb, which can be a good candidate for CRC therapy.
Coordination polymers (CPs) as fascinating materials have been explored in a number of fields due to their diverse properties. In this work, we demonstrate the feasibility of CPs in the facile fabrication of multifunctional composites for establishing an immunoassay. To this end, a zinc(II)-based CP (ZnCP) with adenine as a bridge ligand was employed to integrate with alkaline phosphatase (ALP) and anticarcinoembryonic antigen (anti-CEA) antibody, which produces ALP/anti-CEA@ZnCPs. Benefiting from the adaptive inclusion property of ZnCPs, the integrated ALP and anti-CEA can maintain their original catalytic activity and capture ability to target antigen, respectively. This allows the ALP/anti-CEA@ZnCPs to be a detection antibody for performing an immunoassay. Meanwhile, ZnCP as a host can effectively protect the loaded ALP and anti-CEA against harsh environments. On this basis, by using iron(II)-phenanthroline complex as a signal amplifier, a colorimetric immunoassay for CEA detection was developed, and a low detection limit of 21.1 pg/mL has been achieved. This immunoassay was successfully applied to determine CEA levels in serum samples with good recovery and precision. We believe that this study can not only provide a new method for CEA detection but also open up a new way for the rational design and fabrication of multifunctional composites.
In this work, a novel redox hydrogel was proposed for ultrasensitive label-free electrochemical detection of a carcinoembryonic antigen (CEA). The redox hydrogel composed of cellulose nanocrystals (CNCs), methylene blue (MB), multi-walled carbon nanotubes (MWCNTs), and polydopamine-reduced graphene oxide-gold nanoparticles (PDA–rGO–AuNPs) was formed by electrostatic and hydrophobic interactions among these components. The larger surface to volume ratio, outstanding hydrophilicity, excellent film-forming ability and the gelatinization of CNCs provided the premise for the formation of a gel with excellent properties including larger specific surface area (101.05 m2 g−1), better adhesive ability to glassy carbon electrodes (GCEs), etc. The addition of MWCNTs to hydrogel could improve the adsorption of redox MB. The synthesized PDA–rGO–AuNPs gel was integrated into a hydrogel not only for improving the conductivity but also for providing more sites for immobilization of antibodies. The obtained CNC–MB–MWCNT–PDA–rGO–AuNPs gel was then applied to modify GCE and the gel/GCE demonstrated higher stability and exhibited a strong redox performance (current signal appeared at −0.156 V (vs. Ag/AgCl)). The immunoassay platform was constructed after the gel/GCE was incubated with anti-CEA and blocked by bovine serum albumin (BSA) in succession. The proposed immunosensor exhibited a wider linear range from 1 fg mL−1 to 200 ng mL−1 with an ultralow detection limit of 0.011 fg mL−1 (at a signal to noise ratio of 3). Furthermore, the immunosensor demonstrated higher selectivity, excellent reproducibility, remarkable stability, and better reliability for real sample analysis, which implied a promising potential for the determination of CEA in clinical application.
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