In vivo molecular mapping of the tumor microenvironment in an azoxymethane-treated mouse model of colon carcinogenesis.

Background And Objective: Development of miniaturized imaging systems with molecular probes enables examination of molecular changes leading to initiation and progression of colorectal cancer in an azoxymethane (AOM)-induced mouse model of the disease. Through improved and novel studies of animal disease models, more effective diagnostic and treatment strategies may be developed for clinical translation. We introduce use of a miniaturized multimodal endoscope with lavage-delivered fluorescent probes to examine dynamic microenvironment changes in an AOM-treated mouse model.

Dual optical modality endoscopic imaging of cancer development in the mouse colon.

Background And Objective: We utilize a miniature, dual-modality endoscope that combines fluorescence-based surface magnifying chromoendoscopy (SMC) and optical coherence tomography (OCT) to follow the anatomical changes that occur during adenoma development in the mouse colon.

Materials And Methods: Twenty-five mice were treated with the carcinogen azoxymethane (AOM) to induce tumor development in the distal colon, or were treated with saline as control, and were imaged over six months. OCT detects adenoma number with high sensitivity and specificity and can measure lesion size.

Light-activated content release from liposomes.

Successful integration of diagnostic and therapeutic actions at the level of individual cells requires new materials that combine biological compatibility with functional versatility. This review focuses on the development of liposome-based functional materials, where payload release is activated by light. Methods of sensitizing liposomes to light have progressed from the use of organic molecular moieties to the use of metallic plasmon resonant structures.

NIR-activated content release from plasmon resonant liposomes for probing single-cell responses.

Technological limitations have prevented the interrogation and manipulation of cellular activity in response to bioactive molecules within model and living systems that is required for the development of diagnostic and treatment modalities for diseases, such as cancer. In this work, we demonstrate that gold-coated liposomes are capable of encapsulation and on-demand release of signaling molecules with a spatial and temporal resolution leading to activation of individual cells. As a model system, we used cells modified to overexpress a certain G-protein coupled receptor, the CCK2 receptor, and achieved its activation in a single cell via the localized release of its agonist.

Molecular catch and release: controlled delivery using optical trapping with light-responsive liposomes.

Gold-coated liposomes are maneuvered using an optical trap to achieve precise delivery of encapsulated molecular cargo. Movement and payload release from these plasmon resonant nanocapsules are independently controlled using a pulsed trapping beam. This technology enables in vitro delivery of a payload to a selected cell and may be applied to the interrogation of individual cells within their biological microenvironment.

Wavelength-Selective Light-Induced Release from Plasmon Resonant Liposomes.

Biodegradable, spectrally tunable plasmon resonant nanocapsules are created via the deposition of gold onto the surface of 100 nm diameter thermosensitive liposomes. These nanocapsules demonstrate selective release of encapsulated contents upon illumination with light of a wavelength matching their distinct resonance bands, which correspond to 760 and 1210 nm in this study. Spectrally selective release is accomplished through the use of multiple, low intensity laser pulses delivered over a period of less than four minutes, ensuring that illumination affects only the gold-coated liposomes and avoids heating the surrounding media.

Plasmon resonant gold-coated liposomes for spectrally controlled content release.

We recently demonstrated that liposome-supported plasmon resonant gold nanoshells are degradable into components of a size compatible with renal clearance, potentially enabling their use as multifunctional agents in applications in nanomedicine, including imaging, diagnostics, therapy, and drug delivery (Troutman et al., Adv. Mater.

Plasmon resonant gold-coated liposomes for spectrally coded content release.

We have recently introduced liposome-supported plasmon resonant gold nanoshells (Troutman et al., Adv. Mater.