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In recent years, two-photon excited (TPE) materials have attracted great attentions because of their excellent advantages over conventional one-photon excited (OPE) materials, such as deep tissue penetration, three-dimensional spatial selectivity and low phototoxicity. Also, they have been widely applied in lots of field, such as biosensing, imaging, photo-catalysis, photoelectric conversion, and therapy. In this article, we review recent advances in vibrant topic of two-photon fluorescent nanomaterials, including organic molecules, quantum dots (QDs), carbon dots (CDs) and metal nanoclus-ters (MNCs). The optical properties, synthetic methods and important applications of TPE nanomaterials in biomedical field, such as biosensing, imaging and therapy are introduced. Also, the probable challenges and perspectives in the forthcoming development of two-photon fluorescent nanomaterials are addressed.

Researchers have conducted in-depth research on DNA methylation mechanism, which is related to various diseases such as deficiency of imprinted gene and occurrence of tumors. This study provides a novel rapid quantitative detection assay and real-time fluorescence recombinase-aided amplification assay (RAA) for DNA methylation. Firstly, specific sequence of methylation genes was chosen and primers and fluorogenic probe for RAA experiment were designed and synthesized. Lastly, these amplification products were proven by sequencing and analysis. Results showed that the amplification efficiency and template concentration of RAA had linear dependent (R2 > 95%) when the concentration range was 4.64×108 copies/μL˜4.64×104 copies/μL. The test assay can also detect positive samples when the template concentration is below 4.64×104 copies/μL. Remarkably, the entire experiment process only takes 15–20 minutes, so it is beneficial for rapid bedside simple screening of some special DNA methylation sites, such as detection of resistance genes. In a word, this method has very great potential for diseases with DNA methylation in clinical settings, especially if methylation analysis needs to be done quickly and easily.

Microfluidic chip technology is a technology platform that integrates basic operation units such as processing, separation, reaction and detection into microchannel chip to realize low consumption, fast and efficient analysis of samples. It has the characteristics of small volume need of samples and reagents, fast analysis, low cost, automation, portability, high throughout, and good compatibility with other techniques. In this review, the concept, preparation materials and fabrication technology of microfluidic chip are described. The applications of microfluidic chip in immunoassay, including fluorescent, chemiluminescent, surface-enhanced Raman spectroscopy (SERS), and electrochemical immunoassay are reviewed. Look into the future, the development of microfluidic chips lies in point-of-care testing and high throughput equipment, and there are still some challenges in the design and the integration of microfluidic chips, as well as the analysis of actual sample by microfluidic chips.

An inductive coupled plasma mass spectrometry (ICP-MS) method based on gold nanoparticles (AuNPs) and bio-barcode signal amplification was presented for the sensitive detection of gastric cancer related gene. The target DNA, magnetic nanoprobes and SiO2/AuNPs barcode probes were hybridized to form a "sandwich" structure, then a large amount of AuNPs which were amplified by bio-barcode technology were detected by ICP-MS. This method presented a limit of detection as low as 1 fM. The ratio of the background-subtracted 197 Au signals for totally complementary DNA, single-base mismatched DNA, double-base mismatched DNA and totally mismatched DNA was 115:30:16:1, respectively. It's suggested that the complementary and mismatched DNA can be distinguished clearly. This novel ICP-MS biosensor is prospective in DNA detection with high sensitivity and specificity.