Multi-modal imaging agents are desirable for tumor diagnosis because they can provide more information on the tumor than single-modal imaging agents. However, most reported multi-modal imaging agents are dual-modal agents rather than tri-modal agents; therefore, detailed information on the tumor may still be insufficient when such imaging agents are used. To ameliorate this issue, we synthesized a tri-modal imaging agent, composed of gold cluster and gadolinium oxide integrated nanoparticles (denoted as AuGds) using bovine serum albumin (BSA) as the template via a bio-mineralization method. The AuGds exhibit red fluorescence at ∼660 nm for optical imaging, strong X-ray absorption (around 700 HU) for CT imaging, and a high r₁ value (∼12.39 mM⁻¹ s⁻¹) for MR imaging. After being chemically modified with folic acid (FA), the AuGds can specifically target folate receptors on KB tumor cells, and permit in vivo optical, MR, and CT imaging of xenografted tumors. By comparing these three imaging modalities, very clear structural and anatomical information on the in vivo tumor can be obtained. The AuGds show good biocompatibility, quick renal clearance, and do not induce normal tissue toxicity in vivo.

Human papillomavirus (HPV) is an etiological agent of cervical cancer. Yet co-factors are believed to be involved in HPV-mediated carcinogenesis. Polycyclic aromatic hydrocarbons (PAHs) are considered as one of these co-factors. Epidemiologic studies have associated high PAH exposure with increased risk for cancer development. To date, many studies focus on benzo[a]pyrene, however, the role of other PAHs should not be neglected. This study aimed to compare the potential of different PAHs as a co-factor in HPV-mediated carcinogenesis, and to investigate the possible mechanisms involved. The effect of 17 PAHs on high-risk HPV (HPV16) were examined in this study. HPV16 E7 oncogene was expressed in primary cells extracted from baby rat kidney and treated with PAHs. The co-transforming ability of PAHs were measured by colony formation index according to the number and size of transformed colonies. Effects of PAHs on proliferation of HPV-null (C33A) and –infected (CaSki) were examined using CCK-8 assay. Wound healing assay and matrigel invasion chambers were used to investigate effects of PAHs on cell motility and invasivion of HPV-null (MCF7, C33A) and –infected (SiHa) cells. Benzo[a]pyrene (BaP), dibenz[a,h]anthracene (DBA) and indeno[1,2,3-cd]pyrene (IDP) showed the greatest co-transforming potential in the baby rat kidney cell system. Short-term exposure to BaP, DBA, IDP and pyrene (PR) did not affect proliferation of C33A or CaSki cells, however, long-term exposure of these four PAHs led to dramatic increase in growth rate of CaSki cells by 120–140%. Besides, exposure of PAHs has an effect on cell motility and invasiveness of C33A and SiHa cells, but not for MCF7 cells. Exposure of BaP and DBA enhanced migration (1.26 to 1.40-fold) and invasion (1.68 to 1.94-fold) capacity of C33A cells. Intriguingly, exposure of all four types of PAHs boosted the migration (1.12 to 1.28-fold) and invasion (1.26 to 1.40-fold) capacity of SiHa cells. Our results indicate that exposure to PAHs can be a key co-factor in HPV-related cancer development. They could act on all three stages, namely initiation, promotion and progression. Further study is needed to unveil the mechanisms by which PAHs interact with HPV to cause malignancy.

Fluorescence Resonance Energy Transfer (FRET) has emerged as a predominant, highly sensitive, and homogeneous optical analytical technique in the realm of analytical testing and bio-imaging. Gold nanoparticles (AuNPs) demonstrate a size-dependent, broader absorption range within visible wavelengths owing to the phenomenon of surface plasmon resonance. As a result, they can effectively act as light acceptors, enabling the creation of a donor-acceptor system crucial for achieving precise target analyte analysis. In this comprehensive review, we present an extensive survey of recent research advancements in the field of FRET techniques based on AuNPs for the analytical detection of a wide range of entities, including some biomolecules, pesticides, enzymes, microorganisms, food safety and environmental pollutants. Additionally, we elucidate the procedural strategies and underlying mechanisms involved. Finally, we provide perspectives on the current issues and future efforts surrounding the FRET applications of AuNPs in biological analysis. Overall, this review aims to provide a holistic comprehension of gold nanoparticle applications in life analysis using FRET, while also presenting a promising vision for future endeavors in this domain.

Lead pollution has remained a significant global concern for several decades due to its detrimental effects on the brain, heart, kidneys, lungs, and immune system across all age groups. Addressing the demand for detecting trace amounts of lead in food samples, we have developed a novel biosensor based on fluorescence resonance energy transfer (FRET) from fluorescein R6G to gold nanoclusters (AuNCs-CCY). By utilizing polypeptides as a template, we successfully synthesized AuNCs-CCY with an excitation spectrum that overlaps with the emission spectrum of R6G. Exploiting the fact that Pb²⁺ induces the aggregation of gold nanoclusters, leading to the separation of R6G from AuNCs-CCY and subsequent fluorescence recovery, we achieved the quantitative detection of Pb²⁺. Within the concentration range of 0.002-0.20 μM, a linear relationship was observed between the fluorescence enhancement value (F-F₀) and Pb²⁺ concentration, characterized by the linear equation y = 2398.69x + 87.87 (R² = 0.996). The limit of detection (LOD) for Pb²⁺ was determined to be 0.00079 μM (3σ/K). The recovery rate ranged from 96 % to 104 %, with a relative standard deviation (RSD) below 10 %. These findings demonstrate the potential application value of our biosensor, which offers a promising approach to address the urgent need for sensitive detection of heavy metal ions, specifically Pb²⁺, in food samples.

Novel dual-emissive gold nanoclusters (d-Au NCs) were prepared and applied for the simultaneous detection of phenylalanine or Fe³⁺.

In this study, a novel method based on genistein magnetic molecularly imprinted polymers (Gen-MMIPs) was developed utilizing a surface molecular imprinting technique, in which genistein was used as the template molecule and Fe₃O₄ was used as the carrier. The synthesis of Gen-MMIPs was characterized by using scanning electron microscopy (SEM) and transmission electron microscopy (TEM), which indicated that the diameter of the Gen-MMIPs was approximately 500 nm. Via analysis with a vibrating sample magnetometer (VSM), the saturation magnetization of Gen-MMIPs was determined to be 24.79 emu g⁻¹. Fourier transform infrared (FT-IR) spectroscopy showed that polymer groups were on the surface of the magnetic carrier. Adsorption experiments suggested that the genistein adsorption capability of Gen-MMIPs was 5.81 mg g⁻¹, and adsorption equilibrium was achieved within 20 min. Gen-MMIPs as dispersive solid-phase extraction (dSPE) adsorbents combined with HPLC were used to selectively separate genistein in soy sauce samples, and the recoveries ranged from 85.7 to 88.5% with relative standard deviations (RSDs) less than 5%, which proved that this method can be used for the detection of genistein residues in real samples.