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Immunotherapy is an effective way to mobilize the body's own immune system to confront tumor cells. However, the efficacy of immunotherapy is affected by tumor heterogeneity, and the low therapeutic response to immunotherapy may lead to negative outcomes, which reinforces the urgency for early benefit predictors. Evaluating the infiltration of immune cells in solid tumors and metabolism changes of tumors provide potential response targets for monitoring immune response. Non-invasive imaging identifying prognostic biomarkers can select the beneficiaries of targeted immunotherapy from non-responses. Quantitative biomarkers may eventually improve the cancer management, help customize individual treatment plans and predict the treatment outcomes. In this review, we summarize the non-invasive optical molecular imaging methods for monitoring immunotherapy. With the combination of imaging and immunotherapy, the prediction of immunotherapy response may promote the development of precision medicine.

The high proliferation efficiency, redox imbalance, and elevated nucleic acid repair capabilities of tumor cells severely restrict the theranostic efficacy. Selectively interference chaotic tumors with devastating nucleic acid damages (NUDs) properties are expected to overcome theranostic barriers. Here, an exquisite catalytic-based strategy with comprehensive NUDs mechanisms is demonstrated. In this regard, enzyme (glucose oxidase, GOD) symbioses nanozyme Cu3+ x (PO4 )2 through biomineralization (abbreviated as Cu@GOD), GOD can disorder the metabolism by consuming glucose, thereby inhibiting the nutrition supply for nucleic acid repair. GOD-catalyzed H2 O2 guarantees the self-cyclic glutathione depletion and reactive oxygen species generation caused by Cu3+ x (PO4 )2 , resulted the reduced antioxidation defense and enhanced oxidation assault, ensures an indiscriminate NUDs ability. Moreover, the high photothermal effect of Cu3+ x (PO4 )2 induces effective tumor inhibition. Consequently, this substantial multipath NUDs strategy, with potentials of suppressing the cytoprotective mechanisms, amplifying the cellular oxidative stress, and disrupting the redox balance to ensure substantial irreversible NUDs, completely breaks the obstacle of chaotic tumors, providing new conceptual thinking for tumor proliferation inhibition.

Uric acid (UA) is an important biomarker in urine and serum samples for early diagnosis. This study re- ports a fluorescent biosensor based on Poly(cytosine)-templated silver nanoclusters (C-Ag NCs) and uricase for the highly sensitive and fast detection of UA. The strong fluorescence of the C-Ag NCs prepared from poly (cytosine) nucleotides templates could be sensitively quenched by trace amount of H2O2, which produced from oxidation reaction of UA catalyzed by uricase. This biosensor exhibits two linear ranges as 50 nM∼50 μM and 50 μM∼400 μM, with a detection limit of 50 nM. The sensitivity of the biosensor is considerably improved compared with the methods reported in the literature. Furthermore, the detection ability of uric acid in serum samples is confirmed and this C-Ag NCs-based uric acid biosensor shows good promise of practical application.

4-aminothiophenol-modified gold nanoparticles (PATP-AuNPs) were used as colorimetric and Surface Enhanced Raman Scattering (SERS) probes for the sensitive detection of Escherichia coliDH5α, as a model for Gram-negative bacteria. The nano-probes were easy to prepare through Au-S bonding. Under optimized conditions, the PATP-AuNPs surface with positive charge can bind with negatively charged E.coliDH5α via electrostatic adhesion, resulting in a quick color change from red to blue, and also a dramatic SERS signal enhancement from thousands of AuNPs aggregated on the surface of bacteria, which was utilized for both colorimetric and SERS detection of E.coliDH5α. For colorimetric analysis, it is the first time that the classical partial least square (PLS) regression was utilized to deal with the relationship between adsorption and E.coliDH5α concentrations. Excellent linear relationship was observed from 1.1 x 107 to 1.3 x 108 cfu mL-1 with the average relative error (ARE) of 5.430, which was more accurate than the traditional extinction ration method. When coupled with confocal Raman microscope, this PATP-AuNPs probes could be used to detection SERS signals produced from even one single bacterium. This bioassay is rapid, less expensive and convenient for bacteria detection and analysis. Therefore, PATP-AuNPs system as a novel, versatile, on-site and real-time Gram-negative bacteria sensor, would have a wide range of practical applications.

A novel horseradish peroxidase (HRP) electrochemical biosensor based on a MgO nanoparticles (nano-MgO)-chitosan (chit) composite matrix was developed. The morphology of nano-MgO-chit nanocomposite was examined by scanning electron microscopy (SEM). The interaction between nano-MgO-chit nanocomposite matrix and enzyme was characterized with UV-vis spectra. This proposed composite material combined the advantages of inorganic nanoparticles and organic polymer chit. The HRP immobilized in the nanocomposite matrix displayed excellent electrocatalytic activity to the reduction of H2O2 in the presence of hydroquinone as a mediator. The effects of the experimental variables such as solution pH and the working potential were investigated using steady-state amperometry. The present biosensor (HRP-modified electrode) had a fast response towards H2O2 (less than 10 s), and excellent linear relationships were obtained in the concentration range of 0.1–1300 μM, with a detection limit of 0.05 μM (S/N=3). Moreover, the stability and reproducibility of this biosensor were evaluated with satisfactory results.

Poly(toluidine blue) nanowires (PTBNWs) with an average diameter of ca. 200 nm and length of ca. 5 μm were synthesized for the first time using a template-directed electropolymerization strategy with a nanopore polycarbonate (PC) membrane template. Their morphological characterization was carried out by scanning electron microscopy (SEM) and transmission electron microscope (TEM). By electrochemical polymerization, horseradish peroxidase (HRP) was encapsulated in situ in PTBNWs (denoted as PTBNWs-HRP) for potential biosensor applications. PTBNWs-HRP was then modified on a glassy carbon (GC) electrode. In the system obtained, the PTBNWs served as an excellent redox mediator and exhibited high efficiency of electron transfer between the HRP and the GC electrode for the reduction of H2O2. The proposed electrode can be used as an excellent amperometric sensor for H2O2 at −0.1 V with a linear response range covering from 1 μM to 28 mM, a detection limit of 1 μM (based on S/N=3) and a fast response time of less than 8 s.

Morphology, chemical distribution and domain size in poly(ethylene terephthalate)/high-density poly(ethylene) (PET/HDPE) polymer blends of various ratios prepared with and without maleic anhydride have been analyzed with confocal Raman mapping and SEM. The ratioimage method introduced here allows us to obtain enhanced chemical images with higher contrast and reliability. Compatibility numbers (Nc) are calculated to evaluate the compatibility of the blends. The incompatible polymer blends show heterogeneous distribution with phase separation behavior, while the semicompatible blends prepared with maleic anhydride show much smaller subphase distributions with less distinct interphases. After the blending modification by maleic anhydride of only 0.5%, the viscosity status and dispersibility between PET and HDPE could be substantially improved, and the interactions that exist between the two phases have also been proved by ATR-FT-IR results. High-spatial-resolution confocal Raman mapping coupled with the ratioimage method provides a very attractive way to characterize the compatibility and phase behavior of the polymer blend through different blending methodologies. Copyright © 2006 John Wiley & Sons, Ltd.

The adsorption modes of 4-amino-3-hydrazino-5-mercapto-1,2,4-trizole (purpald) self-assembled monolayers (SAMs) formed on SERS-active silver and gold electrodes were comparatively studied using surface-enhanced Raman scattering (SERS), and the self-assembling procedures were investigated by the Raman mapping technique. Purpald SAMs adopted a titled orientation with S, N2 atoms anchoring to the silver electrode and the N7H2 close to the surface, whereas purpald stood up on the gold electrode through S, N5 atoms and with N8H2 adjacent to the surface. The density functional theory (DFT) at the level of B3LYP was performed to help explain their different adsorption behaviors on the silver and gold electrodes. Copyright © 2006 John Wiley & Sons, Ltd.

DNAzymes, screened through in vitro selection, have shown great promise as molecular tools in the design of biosensors and nanodevices. The catalytic activities of DNAzymes depend specifically on cofactors and show multiple enzymatic turnover properties, which make DNAzymes both versatile recognition elements and outstanding signal amplifiers. Combining nanomaterials with unique optical, magnetic and electronic properties, DNAzymes may yield novel fluorescent, colorimetric, surface-enhanced Raman scattering (SERS), electrochemical and chemiluminescent biosensors. Moreover, some DNAzymes have been utilized as functional components to perform arithmetic operations or as “walkers” to move along DNA tracks. DNAzymes can also function as promising therapeutics, when designed to complement target mRNAs or viral RNAs, and consequently lead to down-regulation of protein expression. This feature article focuses on the most significant achievements in using DNAzymes as recognition elements and signal amplifiers for biosensors, and highlights the applications of DNAzymes in logic gates, DNA walkers and nanotherapeutics.

An electrochemical sensor based on L-cysteine SAM imprinted by L-serine has been developed for the detection of L-serine. The sensor shows some entantioselectivity toward L-serine and a stable response establishes within 5 min. The peak current intensity of potassium ferricyanide quantified by differential pulse voltammetry (DPV) decreased linearly with increasing L-serine concentration from 10 to 100 μM with a gradient of 20.91 nA μM−1. The detection limit was 4.32 μM. The coefficient of enantiometric selectivity of the molecularly imprinted SAM was about 3.0. Compounds with similar structure as serine caused much less response.