In Vitro Selection of Cancer Cell-Specific Molecular Recognition Elements from Amino Acid Libraries

A Fluorescent Carbon Nanotube Sensor Detects the Metastatic Prostate Cancer Biomarker uPA

Therapeutic outcomes in patients with prostate cancer are hindered by the inability to discern indolent versus aggressive disease. To address this problem, we developed a quantitative fluorescent nanosensor for the cancer biomarker urokinase plasminogen activator (uPA). We used the unique fluorescent characteristics of single-walled carbon nanotubes (SWCNT) to engineer an optical sensor that responds to uPA via optical bandgap modulation in complex protein environments. The sensing characteristics of this construct were modulated by passivation of the hydrophobic SWCNT surface with bovine serum albumin (BSA). The sensor enabled quantitative detection of known uPA concentrations in human blood products. These experiments potentiate future use of this technology as a rapid, point-of-care sensor for biomarker measurements in patient fluid samples. We expect that further work will develop a method to discern aggressive vs indolent prostate cancer and reduce overtreatment of this disease.

Noninvasive ovarian cancer biomarker detection via an optical nanosensor implant

Patients with high-grade serous ovarian carcinoma (HGSC) exhibit poor 5-year survival rates, which may be significantly improved by early-stage detection. The U.S. Food and Drug Administration-approved biomarkers for HGSC-CA-125 (cancer antigen 125) and HE4 (human epididymis protein 4)-do not generally appear at detectable levels in the serum until advanced stages of the disease. An implantable device placed proximal to disease sites, such as in or near the fallopian tube, ovary, uterine cavity, or peritoneal cavity, may constitute a feasible strategy to improve detection of HGSC. We engineered a prototype optical sensor composed of an antibody-functionalized carbon nanotube complex, which responds quantitatively to HE4 via modulation of the nanotube optical bandgap. The complexes measured HE4 with nanomolar sensitivity to differentiate disease from benign patient biofluids. The sensors were implanted into four models of ovarian cancer, within a semipermeable membrane, enabling the optical detection of HE4 within the live animals. We present the first in vivo optical nanosensor capable of noninvasive cancer biomarker detection in orthotopic models of disease.

The emerging role of nanomaterials in immunological sensing - a brief review

Nanomaterials are beginning to play an important role in the next generation of immunological assays and biosensors, with potential impacts both in research and clinical practice. In this brief review, we highlight two areas in which nanomaterials are already making new and important contributions in the past 5-10 years: firstly, in the improvement of assay and biosensor sensitivity for detection of low abundance proteins of immunological significance, and secondly, in the real-time and continuous monitoring of protein secretion from arrays of individual cells. We finish by challenging the immunology/sensing communities to work together to develop nanomaterials that can provide real-time, continuous, and sensitive molecular readouts in vivo, a lofty goal that will require significant collaborative effort.

In Vivo Biosensing: Progress and Perspectives

In vivo biosensors are emerging as powerful tools in biomedical research and diagnostic medicine. Distinct from "labels" or "imaging", in vivo biosensors are designed for continuous and long-term monitoring of target analytes in real biological systems and should be selective, sensitive, reversible and biocompatible. Due to the challenges associated with meeting all of the analytical requirements, we found relatively few reports of research groups demonstrating devices that meet the strict definition in vivo. However, we identified several case studies and a range of emerging materials likely to lead to significant developments in the field.

Tumor-targeting peptides from combinatorial libraries

Cancer is one of the major and leading causes of death worldwide. Two of the greatest challenges in fighting cancer are early detection and effective treatments with no or minimum side effects. Widespread use of targeted therapies and molecular imaging in clinics requires high affinity, tumor-specific agents as effective targeting vehicles to deliver therapeutics and imaging probes to the primary or metastatic tumor sites. Combinatorial libraries such as phage-display and one-bead one-compound (OBOC) peptide libraries are powerful approaches in discovering tumor-targeting peptides. This review gives an overview of different combinatorial library technologies that have been used for the discovery of tumor-targeting peptides. Examples of tumor-targeting peptides identified from each combinatorial library method will be discussed. Published tumor-targeting peptide ligands and their applications will also be summarized by the combinatorial library methods and their corresponding binding receptors.