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Kai Cheng

Bio: Kai Cheng is an academic researcher from Stanford University. The author has contributed to research in topics: Fluorescence-lifetime imaging microscopy & Magnetic nanoparticles. The author has an hindex of 33, co-authored 78 publications receiving 6563 citations. Previous affiliations of Kai Cheng include Brown University & University of Vermont.


Papers
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Journal ArticleDOI
TL;DR: A rapidly excreted NIR-II fluorophore based on a synthetic 970-Da organic molecule (CH1055) that allowed targeted molecular imaging of tumours in vivo when conjugated with anti-EGFR Affibody and allowed precise image-guided tumour-removal surgery.
Abstract: Fluorescent imaging of biological systems in the second near-infrared window (NIR-II) can probe tissue at centimetre depths and achieve micrometre-scale resolution at depths of millimetres. Unfortunately, all current NIR-II fluorophores are excreted slowly and are largely retained within the reticuloendothelial system, making clinical translation nearly impossible. Here, we report a rapidly excreted NIR-II fluorophore (∼90% excreted through the kidneys within 24 h) based on a synthetic 970-Da organic molecule (CH1055). The fluorophore outperformed indocyanine green (ICG)—a clinically approved NIR-I dye—in resolving mouse lymphatic vasculature and sentinel lymphatic mapping near a tumour. High levels of uptake of PEGylated-CH1055 dye were observed in brain tumours in mice, suggesting that the dye was detected at a depth of ∼4 mm. The CH1055 dye also allowed targeted molecular imaging of tumours in vivo when conjugated with anti-EGFR Affibody. Moreover, a superior tumour-to-background signal ratio allowed precise image-guided tumour-removal surgery. A renally cleared, water-soluble dye emitting in the near-infrared-imaging (NIR)-II window outperforms a clinically approved NIR-I dye in the in vivo imaging of tumours and their nearby blood and lymphatic vasculatures.

1,160 citations

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TL;DR: This tutorial review summarizes the recent advances in the chemical synthesis and potential applications of monodisperse magnetic nanoparticles and outlines the surface, structural, and magnetic properties of these nanoparticles for biomedicine and magnetic energy storage applications.
Abstract: This tutorial review summarizes the recent advances in the chemical synthesis and potential applications of monodisperse magnetic nanoparticles. After a brief introduction to nanomagnetism, the review focuses on recent developments in solution phase syntheses of monodisperse MFe2O4, Co, Fe, CoFe, FePt and SmCo5 nanoparticles. The review further outlines the surface, structural, and magnetic properties of these nanoparticles for biomedicine and magnetic energy storage applications.

1,060 citations

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TL;DR: A series of low-bandgap donor/acceptor copolymers with tunable emission wavelengths of 1,050-1,350 nm allows for in vivo, deep-tissue and ultrafast imaging of mouse arterial blood flow with an unprecedented frame rate of >25 frames per second.
Abstract: In vivo fluorescence imaging in the second near-infrared window (1.0-1.7 μm) can afford deep tissue penetration and high spatial resolution, owing to the reduced scattering of long-wavelength photons. Here we synthesize a series of low-bandgap donor/acceptor copolymers with tunable emission wavelengths of 1,050-1,350 nm in this window. Non-covalent functionalization with phospholipid-polyethylene glycol results in water-soluble and biocompatible polymeric nanoparticles, allowing for live cell molecular imaging at >1,000 nm with polymer fluorophores for the first time. Importantly, the high quantum yield of the polymer allows for in vivo, deep-tissue and ultrafast imaging of mouse arterial blood flow with an unprecedented frame rate of >25 frames per second. The high time-resolution results in spatially and time resolved imaging of the blood flow pattern in cardiogram waveform over a single cardiac cycle (~200 ms) of a mouse, which has not been observed with fluorescence imaging in this window before.

444 citations

Journal ArticleDOI
TL;DR: Although all of these attempts were successful in principle, there were significant limitations associated with the use of high-intensity UV or visible light in the photo-activation process.
Abstract: Although all of these attempts were successfulin principle, there were significant limitations associated withthe use of high-intensity UV or visible light in the photo-activation process. Excessive exposure to UV light can causephotoreactions in nucleic acids and result in cellular damage.Furthermore, short-wavelength UV or visible light does notpenetrate into tissue very far, which limits its utility for deep-tissue imaging by photoactivation of the caged compounds.Alternatively, multiphoton photolysis with long-wavelengthexcitation has been used to enable deep-tissue imaging and totarget gene expression

428 citations

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TL;DR: Low pH-responsive PHNPs of Fe(3)O(4) can be exploited as a cisplatin delivery vehicle for target-specific therapeutic applications, and is reported to be able to target to breast cancer SK-BR-3 cells with IC(50) reaching 2.9 muM, much lower than 6.8 muM needed for free cisPlatin.
Abstract: We report a new approach to cisplatin storage and release using porous hollow nanoparticles (PHNPs) of Fe3O4. We prepared the PHNPs by controlled oxidation of Fe NPs at 250 °C followed by acid etch...

426 citations


Cited by
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28 Jul 2005
TL;DR: PfPMP1)与感染红细胞、树突状组胞以及胎盘的单个或多个受体作用,在黏附及免疫逃避中起关键的作�ly.
Abstract: 抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1(PfPMP1)与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用,在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员,通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

18,940 citations

Journal ArticleDOI
TL;DR: This Perspective explores and explains the fundamental dogma of nanoparticle delivery to tumours and answers two central questions: ‘ how many nanoparticles accumulate in a tumour?’ and ‘how does this number affect the clinical translation of nanomedicines?'
Abstract: This Perspective explores and explains the fundamental dogma of nanoparticle delivery to tumours and answers two central questions: ‘how many nanoparticles accumulate in a tumour?’ and ‘how does this number affect the clinical translation of nanomedicines?’

3,335 citations

Journal ArticleDOI
TL;DR: This review discusses various nanomaterials that have been explored to mimic different kinds of enzymes and covers their kinetics, mechanisms and applications in numerous fields, from biosensing and immunoassays, to stem cell growth and pollutant removal.
Abstract: Over the past few decades, researchers have established artificial enzymes as highly stable and low-cost alternatives to natural enzymes in a wide range of applications. A variety of materials including cyclodextrins, metal complexes, porphyrins, polymers, dendrimers and biomolecules have been extensively explored to mimic the structures and functions of naturally occurring enzymes. Recently, some nanomaterials have been found to exhibit unexpected enzyme-like activities, and great advances have been made in this area due to the tremendous progress in nano-research and the unique characteristics of nanomaterials. To highlight the progress in the field of nanomaterial-based artificial enzymes (nanozymes), this review discusses various nanomaterials that have been explored to mimic different kinds of enzymes. We cover their kinetics, mechanisms and applications in numerous fields, from biosensing and immunoassays, to stem cell growth and pollutant removal. We also summarize several approaches to tune the activities of nanozymes. Finally, we make comparisons between nanozymes and other catalytic materials (other artificial enzymes, natural enzymes, organic catalysts and nanomaterial-based catalysts) and address the current challenges and future directions (302 references).

2,951 citations

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TL;DR: The in vitro and in vivo biocompatibility and biotranslocation of MSNs are discussed in relation to their chemophysical properties including particle size, surface properties, shape, and structure.
Abstract: In the past decade, mesoporous silica nanoparticles (MSNs) have attracted more and more attention for their potential biomedical applications. With their tailored mesoporous structure and high surface area, MSNs as drug delivery systems (DDSs) show significant advantages over traditional drug nanocarriers. In this review, we overview the recent progress in the synthesis of MSNs for drug delivery applications. First, we provide an overview of synthesis strategies for fabricating ordered MSNs and hollow/rattle-type MSNs. Then, the in vitro and in vivo biocompatibility and biotranslocation of MSNs are discussed in relation to their chemophysical properties including particle size, surface properties, shape, and structure. The review also highlights the significant achievements in drug delivery using mesoporous silica nanoparticles and their multifunctional counterparts as drug carriers. In particular, the biological barriers for nano-based targeted cancer therapy and MSN-based targeting strategies are discussed. We conclude with our personal perspectives on the directions in which future work in this field might be focused.

2,251 citations