14 research outputs found
Application of Cucurbit[n]urils Immobilization in Chemosensor Microarray and Molecular Electronics
A supramolecular cucurbit[8]uril-based rotaxane chemosensor for the optical tryptophan detection in human serum and urine
Sensing small biomolecules in biofluids remains challenging for many optical chemosensors based on supramolecular host-guest interactions due to adverse interplays with salts, proteins, and other biofluid components. Instead of following the established strategy of developing alternative synthetic binders with improved affinities and selectivity, we report a molecular engineering approach that addresses this biofluid challenge. Here we introduce a cucurbit[8]uril-based rotaxane chemosensor feasible for sensing the health-relevant biomarker tryptophan at physiologically relevant concentrations, even in protein- and lipid-containing human blood serum and urine. Moreover, this chemosensor enables emission-based high-throughput screening in a microwell plate format and can be used for label-free enzymatic reaction monitoring and chirality sensing. Printed sensor chips with surface-immobilized rotaxane-microarrays are used for fluorescence microscopy imaging of tryptophan. Our system overcomes the limitations of current supramolecular host-guest chemosensors and will foster future applications of supramolecular sensors for molecular diagnostics
Cucurbit[n]uril-Immobilized Sensor Arrays for Indicator-Displacement Assays of Small Bioactive Metabolites
The patterned immobilization of chemosensors into nano/microarrays has often boosted utilization in diagnostics and environmental sensing applications. While this is a standard approach for biosensors, e.g., with antibodies, other proteins, and DNA, arraying is not yet adopted widely for supramolecular chemosensors which are still predominantly used in solution systems. Here we introduce the patterned immobilization of cucurbit[n]urils (CBn) into multiplexed microarrays and elucidate their prospects for the advancement of surface-bound indicator-displacement assays to detect small molecule analytes. The microarrays were generated by microchannel cantilever spotting of functionalized CBn and subsequent self-assembly of the corresponding indicator dyes from solution. Enhanced sensitivity of surface-bound microarrays was established in demonstrations with small bioactive metabolites (spermine, amantadine, and cadaverine) compared to bulk assays. Furthermore, the integration of the CBn/indicator microarrays into microfluidic channels provides an efficient route for real-time monitoring of the sensing process, allows easier handling, and reduces need for analyte volume. The concept was further extended to differential sensing of analytes on diplex or multiplex CBn/indicator microarrays, opening up a route for multicomponent sensing of small molecule analytes in complex liquids
Rapid Capture of Cancer Extracellular Vesicles by Lipid Patch Microarrays
Extracellular vesicles (EVs) contain various bioactive molecules such as DNA, RNA, and proteins, and play a key role in the regulation of cancer progression. Furthermore, cancer-associated EVs carry specific biomarkers and can be used in liquid biopsy for cancer detection. However, it is still technically challenging and time consuming to detect or isolate cancer-associated EVs from complex biofluids (e.g., blood). Here, a novel EV-capture strategy based on dip-pen nanolithography generated microarrays of supported lipid membranes is presented. These arrays carry specific antibodies recognizing EV- and cancer-specific surface biomarkers, enabling highly selective and efficient capture. Importantly, it is shown that the nucleic acid cargo of captured EVs is retained on the lipid array, providing the potential for downstream analysis. Finally, the feasibility of EV capture from patient sera is demonstrated. The demonstrated platform offers rapid capture, high specificity, and sensitivity, with only a small need in analyte volume and without additional purification steps. The platform is applied in context of cancer-associated EVs, but it can easily be adapted to other diagnostic EV targets by use of corresponding antibodies
A supramolecular cucurbit[8]uril-based rotaxane chemosensor for the optical tryptophan detection in human serum and urine
Sensing small biomolecules in biofluids using host-guest chemosensors remains challenging, in part due to the impact of interfering components. Here, the authors develop a dual-macrocyclic rotaxane for tryptophan detection which can function in biofluids such as human serum and urine
α-Cyclodextrins Polyrotaxane Loading Silver Sulfadiazine
As a drug carrier, polyrotaxane (PR) has been used for targeted delivery and sustained release of drugs, whereas silver sulfadiazine (SD-Ag) is an emerging antibiotic agent. PR was synthesized by the use of α-cyclodextrin (CD) and poly(ethylene glycol) (PEG), and a specific antibacterial material (PR-(SD-Ag)) was then prepared by loading SD-Ag onto PR with different mass ratios. The loading capacity and the encapsulation efficiency were 90% at a mass ratio of 1:1 of PR and SD-Ag. SD-Ag was released stably and slowly within 6 d in vitro, and its cumulative release reached more than 85%. The mechanism of PR loading SD-Ag might be that SD-Ag attached to the edge of α-CD through hydrogen bonding. PR-(SD-Ag) showed a higher light stability than SD-Ag and held excellent antibacterial properties against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus)
An antigen self-assembled and dendritic cell-targeted nanovaccine for enhanced immunity against cancer
The rise of nanotechnology has opened new horizons for cancer immunotherapy. However, most nanovaccines fabricated with nanomaterials suffer from carrier-related concerns, including low drug loading capacity, unpredictable metabolism, and potential systemic toxicity, which bring obstacles for their clinical translation. Herein, we developed an antigen self-assembled nanovaccine, which was resulted from a simple acryloyl modification of the antigen to induce self-assembly. Furthermore, a dendritic cell targeting head mannose monomer and a mevalonate pathway inhibitor zoledronic acid (Zol) were integrated or absorbed onto the nanoparticles (denoted as MEAO-Z) to intensify the immune response. The synthesized nanovaccine with a diameter of around 70 nm showed successful lymph node transportation, high dendritic cell internalization, promoted costimulatory molecule expression, and preferable antigen cross-presentation. In virtue of the above superiorities, MEAO-Z induced remarkably higher titers of serum antibody, stronger cytotoxic T lymphocyte immune responses and IFN-γ secretion than free antigen and adjuvants. In vivo, MEAO-Z significantly suppressed EG7-OVA tumor growth and prolonged the survival time of tumor-bearing mice. These results indicated the translation promise of our self-assembled nanovaccine for immune potentiation and cancer immunotherapy
Thermoresponsive Self-Assembled β‑Cyclodextrin-Modified Surface for Blood Purification
For patients with liver failure,
bilirubin (BR) is one of the endogenous toxins in their blood. Although
blood purification can remove the bilirubin from the body in clinics,
the detoxification system needs to be improved, and the cost needs
to be decreased. In the present study, we developed a recyclable model
surface that can strongly remove bilirubin. We first prepared <i>adamantane</i> (<i>Ad</i>) on a model gold surface
by self-assembly. Then, we integrated the <i>β-cyclodextrin
dimer</i> (<i>CDD</i>) onto the surface with host–guest
interactions between one of the CD cavities in the <i>CDD</i> and <i>Ad</i>. We characterized the surface with XPS,
static contact angle measurements, and AFM. In addition, we employed
QCM-D to characterize the preparation process as well as the detoxification
of the surface. We demonstrated that this modified surface could strongly
adsorb bilirubin through host–guest interactions between the
CD cavities in the <i>CDD</i> and bilirubin and that the
detoxification was improved 1.7 times (compared to the surface only
with <i>Ad</i>). Interestingly, after characterization with
QCM-D, this surface could be recycled due to the thermoresponsive
property of the host–guest interaction between the <i>CDD</i> and <i>Ad</i>. After adsorbing the toxin and
increasing the temperature to 45 °C, the <i>CDD</i> with bilirubin could be removed from the surface. Then, the refreshed
surface with <i>CDD</i> could be prepared again at room
temperature. This cycle could be repeated at least 3 times. Additionally,
during each cycle, the modified surface exhibited good detoxification
to bilirubin. This modified surface also showed strong resistance
to plasma proteins, decreasing the adsorption of human serum albumin
(HSA) and fibrinogen (Fg). An in vitro platelet adhesion assay showed
that the adhesion of the platelets on the modified surface decreased
and that the platelets were in an inactivated state. The hemolysis
assay showed that this surface exhibited no hemolysis activity in
the samples to red blood cells (RBCs). The CCK-8 assay showed that
this surface had negligible cytotoxicity to L929 cells. This work
has taken advantage of the host–guest self-assembly between
β-CD and BR/Ad for special recognizing adsorption, as well as
the thermoresponse of β-CD-Ad inclusion for recyclable application,
and these results demonstrate that this technology has great potential
for removing bilirubin and decreasing clinic costs