D. Paithankar, T. Meyer, R. Blomgren, L. Faupel, A. Lando, R. Anderson
Keywords: acne, nanotechnology, laser treatment, selective photothermolysis, drug delivery, sebaceous follicles, sebaceous glands
Summary:A laser treatment for acne, one of the most common dermatologic conditions, with 150 nm diameter plasmonic resonant particles tuned to absorb near infrared light has been developed. Acne lesions originate from sebaceous follicles; the pathophysiology of acne vulgaris depends on active sebaceous glands and clogged infundibulum, implying that selective destruction of sebaceous glands and restructuring of the infundibulum could be an effective treatment. Unlike hair and blood vessels, sebaceous follicles do not have inherent light absorption to allow for use of near-IR wavelengths for selective photothermolysis. We hypothesized that light-absorbing plasmonic particles could be delivered into sebaceous follicles, enabling local thermal injury by optical pulses delivered to the skin surface. A suspension of topically applied gold coated silica microparticles exhibiting strong plasmon absorption at 800 nm was delivered into human pre-auricular and swine sebaceous follicles in vivo, using mechanical vibration. After exposure to 10-50 J/cm^2, 30 milliseconds, 800 nm diode laser pulses, microscopy revealed preferential thermal injury to sebaceous follicles and glands. Inflammation was mild; gold particles were not retained in swine skin 1 month after treatment, and uptake in other organs was negligible. An independent prospective randomized controlled clinical trials was performed for treatment of moderate to severe facial acne, with assessments of inflammatory lesions and disease severity. The trial showed clinically and statistically significant improvement of inflammatory acne following three treatments given 1 week apart. At 12-weeks post baseline, the mean percent inflammatory lesion count changes were -49% and -22% for the treatment and the sham arms, respectively (p=0.04). Thus, laser treatment after follicular delivery of microparticles enables selective photothermolysis of sebaceous follicles and is a well-tolerated, effective treatment for acne vulgaris.