Near-infrared biophotonics-based nanodrug release systems and their potential application for neuro-disorders

ABSTRACT

Introduction: Near-infrared ray (NIR)-responsive ‘smart’ nanoagents allow spatial and temporal control over the drug delivery process, noninvasively, without affecting healthy tissues and therefore they possess high potential for on-demand, targeted drug/gene delivery. Various NIR-responsive drug/gene delivery techniques are under investigation for peripheral disorders (especially for cancer). Nonetheless, their potential not been extensively examined for brain biomedical application.

Areas covered: This review focuses on NIR-responsive characteristics of different NIR-nanobiophotonics-based nanoagents and associated drug delivery strategies. Together with their ongoing applications for peripheral drug delivery, we have highlighted the opportunities, challenges and possible solutions of NIR-nanobiophotonics for potential brain drug delivery.

Expert opinion: NIR-nanobiophotonics can be considered superior among all photo-controlled drug/gene delivery approaches. Future work should focus on coupling NIR with biocompatible nanocarriers to determine the physiological compatibility of this approach. Their applications should be extended beyond the peripheral body region to brain region. Transient or intermittent NIR exposure strategies may be more accommodating for brain physiological ambience in order to minimize or avoid the possible deleterious thermal effect. In addition, while most studies are centered around the first NIR spectral window (700–1000 nm), the potential of second (1100–1350 nm) and third (1600–1870 nm) windows must be explored.

KEYWORDS:

• Near infrared ray (NIR)
• nanoparticles
• biophotonics
• drug delivery
• cancer
• brain
• and neuro-disorders

Article highlights

• Optical characteristics, in general, are strongly dictated by particle size and therefore nanomaterials have improved optical properties than their macroscopic structures.

• NIR-nanobiophotonics provide unique advantage in utilizing non-ionizing radiation for noninvasive tissue penetration and the NIR based optical resonance has three major purposes in the field of biomedicine: localized heating, localized fluorescence imaging, and localized release of drugs or other chemical substances from the carrier.

• Dependent upon the composition of nanocarriers, NIR-responsive drug delivery can be achieved by three strategies: a) Self-disruption of nanocarriers in response to NIR exposure, b) Disruption of NIR-labile caging bonds, and c) Unlocking of NIR responsive ‘gate-keepers’ caging.

• Transient NIR exposure strategy in conjugation with nanocarriers may be useful for brain specific targeting because cell-damaging photothermal effect is reduced to zero in case of transient NIR exposure.

• Biological perspectives of NIR exposure in different population groups must be delineated before ‘NIR-nanoparticles’ coupling for real-time medical purposes.

• Advances in drug delivery towards clinical trials are results of evolutionary process where numerous trials (and errors) are required to achieve physiological viability of drug carriers. As such, existing challenges of NIR-nanobiophotonics based drug delivery must be addressed to achieve their feasibility for clinical studies.

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Declaration of interest

The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

Additional information

Funding

This work was supported in part by grants R01DA040537, R01DA037838, and R01DA034547 from the National Institutes of Health.